A bit of all of the above. Third party solutions mean some orgs and politicians can slurp up data and provide it to other third parties for kick-backs. Both RTA and third party can be bypassed and in fact would lead to more teens getting into credit card fraud and potentially giving them a criminal background before their careers even get started whereas bypassing RTA would not create yet more criminals.
Gotta feed the prison industrial complex. Small children
the original intended focal point would not be bypassing RTA thus giving good parents time to educate them on risks of websites and the people participating on them. Third party tracking allows people against porn to identify what kinks people are into much like Epstein lured people into compromising positions to blackmail them. Even if that is not their intention their sites will be
hacked to acquire and sell that information for that purpose. With the RTA header none of this is possible.
Until big porn companies, social media companies or any companies use lobbyists to implement RTA it just won't happen. I bring it up when this topic comes up quarterly year over year. I've beaten the dead horse so many times the dust has evaporated. It's rather silly now since the original RTA header was the ICRA PICS header much more complex to implement. Adding a single simple header and looking for a header is trivial which means the obstacles are entirely human made and artificial. Perhaps when governments start creating more expensive laws and penalties around user contributed content things may change.