I'm really not trying to be a dick, but uhh... Look around? The world is literally on fire and efforts to put it out or even to stop pouring more gas on it are put down at every turn by capitalists in the never ending pursuit of more money for it's own sake.
Let's start here: are you a capitalist? Do you own any actual capital? I don't mean your own house or car, that is personal property not private property or anything resembling the means of production.
I ask because many people consider themselves capitalist when really they are just workers who happen to own a bit of personal property, and they make themselves essentially useful pawns for actual capitalists.
And, if you're not an actual capitalist, why are you so pro capitalism?
You'd rather have the climate crisis as it currently stands. I think you'll change your tune on that in coming decades but by then it'll be far too late to actually do anything about it. You're also more insulated to it's effects than many millions of people around the world who are already losing their lives, homes, livelihoods, etc and this is only a sniff of what's to come. Also, peasants in feudal times on average had more time off, made more money comparatively, and were able to travel more (yes, even serfs) than your average American currently. The chains just look a little different, they aren't gone.
We've got 8 billion people to feed and are doing a terrible job of it. Take under half of Elon's wealth alone and you could feed the entire world, yet instead we laud these modern day dragons for their "success," instead of slaying them for the good of the people. It's easier to make things worse for you, than better for you. Billions of people currently suffering terribly for the profit of others would vehemently disagree. Also, just because the unknown is uncertain doesn't mean it should be feared. We know capitalism isn't working for the planet itself, yet people would rather stick to it because it's enriched a small fragment of humanity. You happen to be in the side of the boat that isn't currently underwater, but make no mistake that the water is pouring in.
You are not a capitalist.
You are a worker, so why look out for the interests of an entirely different class that doesn't do the same for you?
Therein lies the exact problem: profit is the only motive. And to get profit, capitalists have shown they are willing to do everything, damn the consequences to others, to society, to the planet. Climate change isn't a whoopsie, starving, desperate people aren't a whoopsie, train derailments aren't a whoopsie, even most wars (every American involved war since WW2) are not a whoopsie. They are all the predictable results of capitalists choosing to rake in more profits at the expense of you and I.
Why would they need to set up their own governments when they control ours? How exactly are they constrained? Google is arguably more powerful than most nations' governments. Sure, most of that is soft power, but if trends continue it won't stay soft for much longer.