I fundamentally disagree with most of your points. It might work for a usecase you have in mind but in general, it can't work. And it assumes that the world is

I fundamentally disagree with most of your points. It might work for a usecase you have in mind but in general, it can't work. And it assumes that the world is a perfect place where the incentives are aligned and that ISPs cooperates and that you'd actually want to expose your phone. As if the tech we have (mobile networks, phone batteries, coverage) would allow for it, which it don't. And somehow denial of service attacks is only worth mentioning when you have a dedicated PC with proper 100+mbit internet but not when you have a battery powered phone with wireless connection? And I truly fail to see how all anyone could even argue that all that complexity would be better than direct access.