Yeah, it's read-only.
IMO that's still better than other sites, where they don't federate at all.
On Reddit, you can screencap something, and paste a static image. You can't see the comments underneath at all.
I expect instances that don't fully federate will grow slower, so it won't matter, most content will be on instances that are open to fully connecting with others.
Of course. The people who run cities are almost always multi-millionare landowners and their friends all have real estate investments too.
They either make it illegal to build densely, or they put obstructions in the permitting process to restrict how much is created.