> I agree that the ideology of growth at all costs is problematic, but it's how our society is structured right now

With this mindset, nothing ever changes. No social problem was ever solved without looking at it from a social/political perspective. If you agree that growth ideology is problematic, then that's what you need to dismantle.

> To be fair, the declining fertility rate will probably solve a bunch of environmental issues

I think this is just wrong. The problem is the lifestyle: the throwaway culture and abundant consumption of throwaway goods. We could be just as many billions living OK in our environment, but you could have just 100 million average middle-class westerners continuing to fuck up nature (just slightly slower).