The problem is that content-creation has become prohibitively laborious and expensive. Don't even think about creating a Battlefield level (or similar levels) without having a team of people working on it.

3D models aren't much better. You can easily re-texturing and create new content this way, but adding new models, animations and AI requires huge amount of polish to be somewhere near AAA quality.

Of course I completely agree on the community aspect. Forums have been dying for a long time and left a vast graveyard of former communities. But this is mostly due to social media and how newer generations are using the internet. We have a continuing trend of centralization which has affected the gaming sector big time.