Because if I can do nothing and make you do it, you solve it for me, for free. They'll make some argument (like western nations having used up the energy (and paid for it), and want to make them pay for it
again. For a lot of countries that, and nothing else, is the purpose of climate action). Now get to work, taxpayer!
Because for most countries (and certainly for the largest oil producer in the world, Russia), global warming saves greatly on winter fuel use and increases agricultural harvests AND allows them to keep their population happy (because nothing keeps populations calm like cheap fuel/energy). That is the net effect, today.
Because for a lot of countries that really are the beneficiaries of causing global warming, ie. the oil producer countries, Russia, Saudi Arabia, US, Venezuela, Norway, and many small ones Azerbeidjan, causing global warming (ie. selling fossil fuels) is often the only reason they have an economy (mostly all except the US). So they demand a LOT of money, for free, to stop it. And nobody will pay that.
The last argument even goes for countries that are not direct oil or coal producers, like India or China but it's effectively the same argument (China runs on coal, and the country works on exports. Without energy no exports, so their coal usage is still increasing. Ie. same argument as above, they only have an economy because they're causing global warming, just more indirectly than Saudi Arabia)
Because WW2 was won with oil, and so countries that either want to start a war ("or fear they'll be the target/victims of the next big war") want access to oil. This argument goes especially for China, who fear they'll be targeted/"victimized" when they attack half of Asia starting with Taiwan and to a lesser extent for India (who feel they'll be at war with Pakistan, and Bangladesh whether they want to or not, and maybe China too) and even for EU countries (ie. for the ones that matter, France and Germany)
Look up China's oil reserves. You'll be collecting your jaw from the floor, I promise.
Summary: because most governments care about various things ... and not at all about people, about you. Mostly governments not even about their own people and certainly not about the climate where you live. They have a million concerns, a lot of which require fossil fuels, and for the people that compose those governments, climate change just doesn't matter.
Plus, if they can just do nothing, you still have to solve global warming. So doing nothing, aside from being very profitable, is also a great tactic to get you to fix it.