The decision to not build the billing system first, or at all, is what separated the internet from telco culture.

Note that any billing system is also necessarily a surveillance system - someone has to keep the billing information and know who their customers are. The fight is ongoing as to whether cryptocurrency might change this, but you have to accept that any system which allows very large scale money laundering is not going to be tolerated, which puts an upper limit on how successful that project is going to be.

And a billing system doesn't save you from adverts or selling customer information; US cable TV shows that.