For example, it is now >50 years since anthropogenic global warming was first proposed. The first intergovernmental action I can find with a brief search that tackles climate change is the 1992 UN Framework Convention on Climate Change. Legislation surrounding CO2 emissions was not introduced until the 2000's. The matter is still "controversial".
https://en.wikipedia.org/wiki/United_Nations_Framework_Conve...
Some things are demonstrable. When I started finding and reporting cyber security holes to various governments and governmental departments I was hired to help them. They fixed the holes or at the very least they started a public review of cyber security and got the process for better our regulations started.
Don't give in to cynicism.
Western governments have corruption and malaise, true, but government is made of people and most people want to make things better and fairer and our democracies aren't perfect but you can make a difference if you put your best foot forward. You just need to try.