Why did Substack choose the subscription model? Have you considered the micropayment model instead? Personally, I would much rather pay a small fee for each article I read (provided you remove all the barriers to payment) rather than pay a monthly subscription. I'm curious about the pros and cons of each option
In terms of enforcement, I don't think it would be that hard. There are only a handful of ISPs. Manufacturers can either (1) build their own OS's or (2) refuse to do business with any ISP who doesn't implement net neutrality or (3) risk being sued.
Branching is possible but would be a headache for them to maintain.
I don't think this would completely stop them, but I do think it would give some of the organizations fighting for net neutrality another legal avenue to make it a headache for an ISP to go against net neutrality.
(Obviously I'm not a legal expert, just a frustrated developer who is sick of feeling powerless in this fight)