Millions of people died when a possible solution of "hey, everyone, let's stay inside for a couple weeks" could've possibly effectively eradicated the virus does not seem like a great example of humanity's ability to cope with imminent global existential threats. The potential solution(s) to the massive brick wall we're speeding towards are far more inconvenient than "everyone just hang out for a minute." It's radical change to everything in society.
The comparison with Covid is also striking because the only reason a global "don't travel too much" solution couldn't work is due to the nature of capitalism. It's not like we couldn't feed everyone. It's just that some people with too much wouldn't gain as much for a little bit. Which is the same root cause of why solving climate change is impossible without radical change.
Unfortunately, I don't know the answer. I'm quite certain it's not to maintain the status quo, though.