Secondly, the resources we use per dollar of GDP is going down rapidly. Not as fast as GDP is growing, but it is going down. Given that a good portion of our growing GDP is due to growing population, once the "growing population" part of it goes away, it's not unreasonable to expect that resources/$GDP will shrink at the same rate that $GDP grows.
It's not unreasonable -- if we have access to lots of clean energy and we recycle efficiently our footprint will go down substantially. For example, the iPhone 25 will be better than the iPhone 24 yet likely use less resources. And the upgrade cycle for iPhone's is slowing down -- an iPhone 18 will still likely be "good enough".
The biggie is food. Food uses a lot of resources. If we stabilize the population that'll take a lot of strain off, but I believe that we can significantly reduce our resource requirements for food. Right now we grow our food the way we do not because it requires so many resources, but because that's the cheapest way to do so. For example, if we used a lot more greenhouses we'd use a lot less land for the same amount of food, but we don't because greenhouses are more expensive than just using a lot of land. Also, I'm very optimistic about "precision fermentation".