You think preventing climate change is more expensive than not preventing climate change? That's an interesting point of view. I'm not sure the facts agree with you.
Wildfires that burn down houses and gigantic forests every summer, massive storms that take out coastal cities, that kind of stuff tends to have an expensive price tag attached to it.
It's easy to forget, but the most effective first step for individuals who want to prevent climate change is: Reduce. And that costs nothing at all. It actually saves money. Of course there are many other things that ought to be done as well, but let's keep in mind the starting point.
You think consuming less would stop the economy dead in it's tracks. And ... Is that a bad thing? As we know, "economy" means "rich people's yachts".
And just as obviously, reducing consumption is not binary. There's no way to go to zero, nor would anyone seriously propose it. But anyway, with an increasing population and limited global resources, it's inevitable that people will have to reduce at some point, so the disaster you hypothesize would strike us anyway. And in that case, gradual change now is better than catastrophic change later.