IMO "people" would run many of their own servers if it were easy. At the moment, it's not easy because it's not easy to safely open up to the public a server running on your computer/phone, or home network. ISPs benefit from making this hard, and (as best I understand it) the IP4 address space isn't wide enough anyway.
If "people" could run servers on their phones, safely, with minimal effort, they would. They would, because it would be so minimal effort that no-one needed to think "I'm running a server". They should only need to think "I'm available now" and that be it.