> Regulatory compliance (especially FCC common-carrier compliance) is an added cost of doing business which absolutely could be enough to keep a business from starting up.

Have you calculated how much does that really cost? I'd say it's several orders of magnitude lower[0] than the consequence of other regulations that are the real cause there are no more ISPs.

[0] (response to a comment I made wrongly stating it doesn't cost a cent) https://news.ycombinator.com/item?id=15891156