I would argue the opposite. Yes, those "space demanding" hobbies are hard to get into. But there's so many other hobbies and interests people have, and having a

I would argue the opposite. Yes, those "space demanding" hobbies are hard to get into. But there's so many other hobbies and interests people have, and having a few million people packed really close really reduces the effort required to have a niche group of hobbyists or find something niche you care about. In other words. It's much easier to find likeminded people closeby in dense, populated cities.