Virtually everyone gets their internet from an ISP that is regulated in the country that the user lives in. There are no technical barriers to implementing a permitting system in the United States.
Linking connections to real people is self-enforcing when there is a usage-based tax.
[1] https://www.africanews.com/2018/04/13/uganda-s-social-media-...
Those remaining very likely have multiple advantages like advance technical knowledge, connection to powerful people in business / governments, money and legal support in case they end up on wrong side of law. There is very little benefit and lot of effort to catch these unless they are running some kind of criminal organization which adversely affects their government/regime.