I wish I shared your optimism. A deus ex machina solution is extremely unlikely. It would be more effective to attempt to forcibly sieze control of the mechanisms of pollution than to hope for surprise salvation. When you are being actively killed, sometimes violence really is the answer.

Even if we did develop fusion, how long would it take to switch to it and would it even be economical? A ton of places still use coal and other fossil fuels simply because they're cheap or were already built. It's hard to make assumptions about how much fusion would cost when we still don't have it. Nuclear fission's fuel is cheap (cause so little is needed), yet nuclear is still insanely expensive because building the plants is a difficult task mired in red tape and the general public is afraid of it (on that note, I'm not sure how many people even have a concept of fusion beyond perhaps what Spiderman 2 made them believe).

There's also the divide in the world. Even if the rich western countries got fusion, would everyone? The west also got covid vaccines early while much of the rest of the world had to wait. And further drawing on the covid analogy, some countries pretended there wasn't an issue, which already is going on with climate change.

Maybe God will save us.

People that are truly serious about this aren't deluded into thinking we can take shorter showers and solve the problem, but they aren't likely advertising potential effective options on social media. I don't know anyone personally who cares about the climate who doesn't know that more drastic measures need to be taken if anything is to be helped at all. If a company can profit off of something they won't stop unless forced.

Hey, you get enough people together to be effective at tearing down the gates, going where the owners are, and doing what we should have done decades ago, I'll be there with bells on.

Instead people will shout "eat the rich!" on the internet until doomsday, and no dinner will ever be served.

There is a small, specific class of people that must be dealt with to even begin to address this. They hold all the keys, all the cards, all the hard power. Humanity lacks the will. And the owners make fun of people like you for believing trying to reason with them will ever do anything for the long term survival of the species when there's still another dollar to exploit.

If you aren't willing to be a part of handling that problem, you aren't serious either. They own the "justice" systems that would hold them responsible. They own the media that tell most peasants what to think and who to blame. They own the governments that were supposed to regulate them. Force is the only practical option. One the people won't exercise out of either rational fear of the individual consequences, or ignorant faith in their oppressors.

Go ahead and beg instead, I'm sure you believe we can change the outcome peaceably, lol. Scientists and rational people have been for half a century, begging the owners to look at the hard data of what they're doing and stop for the sake of their own species. How has that been going?

And how are you supposed to do that? You can vote, but that is just one person. Look at the election results & polls of green parties & politicians who want to do something. No one actually wants that, otherwise they'd be voting differently. Everyone loves to cry about the big corporations or the bad politicians but none of them want to do anything themselves or be in any way shape or form affected by required measures that are needed to reduce emissions. Because yes, at this stage it will cost us, all of us, and it will just get more and more expensive to fix with each passing year - until there's nothing possible to fix anymore.