The Metropolitan Opera announced Wednesday that the still-untamed coronavirus pandemic has forced it to cancel its entire 2020-21 season, prolonging one of the gravest crises it has faced in its 137-year history and keeping it dark until next September.

The decision is likely to send ripples of concern through New York and the rest of the country, as Broadway theaters, symphony halls, rock venues, comedy clubs, dance spaces and other live arts institutions grapple with the question of when it will be safe again to perform indoors. Far from being a gilded outlier, the Met, the nation’s largest performing arts organization, may well prove to be a bellwether.

The outbreak has kept the 3,800-seat opera house closed since mid-March, sapping it of more than $150 million in revenue and leaving roughly 1,000 full-time employees, including its world-class orchestra and chorus, furloughed without pay since April. Now, with the virus still too much of a threat to allow for a reopening on New Year’s Eve, as hoped, Peter Gelb, the Met’s general manager, is making plans to adapt to a world transformed by the pandemic, including by trying to curb the company’s high labor costs.

“The future of the Met relies upon it being artistically as powerful as ever, if not more so,” Mr. Gelb said in an interview. “The artistic experiences have to be better than ever before to attract audiences back. Where we need to cut back is costs.”

As he canceled the current season, Mr. Gelb announced an ambitious lineup for 2021-22 to reassure donors and ticket buyers that the Met has robust plans. An even more difficult effort will play out offstage: Mr. Gelb said he would ask the company’s powerful unions to agree to cost-cutting concessions that he said would be necessary in the post-pandemic world, and which a number of other prominent performing arts organizations have begun to implement.

The Met plans to return to its stage next September with Terence Blanchard’s “Fire Shut Up in My Bones,” the first time it will mount an opera by a Black composer — a long-overdue milestone, and part of a new focus on contemporary works alongside the ornate productions of canonical pieces for which the company is famous. The Met will also experiment with earlier curtain times, shortening some operas and offering more family fare as it tries to lure back audiences.

The last time the Met sought major labor concessions, in 2014, a bitter battle ensued, and a lockout that would have closed the theater and cut off pay was averted only when the two sides agreed to more modest cuts. This time, negotiations will be held while the theater is already shut and many of its workers — both unionized and not — are not being paid.

Mr. Gelb told the company on Wednesday that the Met would offer to begin paying its work force again during the dark months ahead if the unions agree to “longer-term reductions that will allow the Met to recover in the future.” The disclosure earlier this week that James Levine, the company’s former music director, had received a $3.5 million settlement after the Met fired him in 2018, citing sexual misconduct, could complicate negotiations.

The offer puts employees, who have gone without pay for nearly six months and are dependent on the Met for their health insurance, in a difficult position.

The American Guild of Musical Artists, which represents the company’s choristers, stage directors, dancers and others, said in a statement that “the Met seems uniquely determined to leverage this moment to permanently gut our contract.”

“The Met cannot solve its difficult problems by turning its back on the artists who have built it over generations,” the committee said in the statement.

And the committee that represents the musicians in the orchestra warned that cuts could jeopardize the quality of the company.

“Simply stating that labor costs must be cut is not a solution or plan for the future,” the orchestra committee said in a statement, “especially in light of the fact that no labor costs have been paid by the Met over the last six months.”

“With the Met at risk of artistic failure,” the statement said, “we will insist on a contract that preserves the world-class status of the Met Orchestra so that when we are able to reopen, our audiences will be able to experience performances at the level that they expect and deserve.”

Mr. Gelb said in the interview that he hoped an agreement could be reached, and that some reductions could be restored as box office returned to pre-pandemic levels.

“These are not normal times,” he said. “These are pandemic times. There’s going to be a residual fallout from this that is going to go on for several years.”

Grand opera is in some ways uniquely vulnerable to the pandemic: It is so expensive to produce that it is financially difficult to sustainably perform to reduced-capacity audiences, and it attracts older people, who are among the most vulnerable to the virus. (The average age of Met operagoers was 57 last season.) But the broader question — when will it be safe to hold large-scale indoor performances again in the United States, which has been much less successful at curbing the spread of the coronavirus than many of the nations in Europe where theaters are gingerly beginning to reopen — is being asked throughout the arts world.

It seems unlikely that indoor events with anywhere near regular capacity will be possible until after the wide distribution of a vaccine, and Dr. Anthony S. Fauci, America’s leading infectious disease expert, said this month that it would likely be more than a year before people could feel comfortable returning to theaters without masks.

Other major New York arts organizations, which had canceled performances through early January, are weighing their next steps. The New York Philharmonic said it expected to give an update on its plans in early October, while Carnegie Hall said it would be assessing its next steps in consultation with medical experts and government officials. The Broadway League said that no return date for shows had yet been set.

The impact on arts organizations and artists, often in a precarious financial condition even before the pandemic hit, has been brutal. Now many hard-hit institutions that have had their activities put on hold or curtailed are taking extraordinary steps to survive.

The Boston Symphony Orchestra, one of the richest ensembles in the nation, announced this month that its players had agreed to a new three-year contract reducing their pay by an average of 37 percent in the first year, and increasing as the orchestra’s revenues return. The San Francisco Opera agreed to a new deal that will cut its orchestra’s salary in half this season, gaining back some ground over the next two years.

The Met, whose budget of roughly $300 million in a normal season makes it the biggest performing arts organization in the nation, is taking a series of steps to try to ensure its survival and adapt to a changed world. It is publicizing its entire 2021-22 season, months ahead of schedule, partly in the hopes that people who bought tickets to canceled performances — roughly $20 million in tickets has already been sold — can be persuaded to exchange them for the newly announced operas.

Mr. Gelb said that even when the Met can reopen, audiences will likely be slow to return — with attendance perhaps half of what it was in pre-pandemic times. So the company will add more early 7 p.m. curtain times, which people have called for in surveys. It will shorten some operas, presenting Mussorgsky’s “Boris Godunov” in a two-and-a-half-hour version with no intermission; trimming Handel’s “Rodelinda”; and removing the second intermission from Puccini’s “Madama Butterfly.” It will expand its offerings for families, presenting a new 90-minute, English-language “Cinderella” — an adaptation of Massenet’s “Cendrillon” — as well as its popular abridged “Magic Flute.”

And the Met will work to increase the diversity of its offerings. While “Fire Shut Up in My Bones” was originally planned for a later season, Mr. Gelb decided that with calls for racial justice resonating through the nation and the music world, it should be given pride of place next year: opening night of the Met’s comeback season. The company is also adding three Black composers — Valerie Coleman, Jessie Montgomery and Joel Thompson — to the commissioning program it runs with Lincoln Center Theater.

“We’re trying to send a signal that the Met wants to meet the times in which we live head on,” Mr. Gelb said. “Given all the calls for greater social justice and diversity, we think it’s appropriate, after being off for a year, to come back in a way that demonstrates the Met’s social responsibility.”

On a contrary, a lot of independent performing arts producers are not willing to give up on their productions and taking measures to go ahead with the new knowledge and protocols to make the event happen at all cost.