Yes, but unlike with Email, I can host my own instance and expect it to federate with other major instances. If you have a residential IP then you can forget hosting you own Email because major players don't want anything to do with you due to spam.
It's possible this can happen to the fediverse, but I'm more optimistic about it because the fediverse is generally not a business venture like Email is now.
It would be, but the economy was built on perpetual growth schemes.
Don't forget, the economy is here to be served by us, not the other way around!