ISPs in many countries by law don't have the power to exclude things they don't like and competition prevents other abuses. If there are no laws like that in your country and not enough competition, you can zoom out to the problem of capitalism with incentives to gain monopoly and capture regulatory agencies. With such problem mesh networks are going to be monopolized in exactly the same way, because somebody has to maintain them to make it work well and with enough usefulness people would rather pay a subscription fee for a working service than rely on unreliable volunteers, and capitalists would rather buy everyone who offers the service early on than let competitive market happen and we are back to square one.

What I'm trying to say is that if mesh network is a solution, you have a much bigger problem than you realize.