I have a pet theory that these business models paper over the vast worthlessness of many modern technologies. That the value of Facebook is not in it's technologies or network, but rather in the arbitrage of the value of data when combined. We pay for the nearly worthless service of facebook, with our nearly worthless data. Facebook combines that data with other data from other people, and create data that is extremely valuable for advertisers.

The important bit of this theory is that Facebook is presumed nearly worthless. What that means is that outlawing their combining or collection of data from users wouldn't cause their service to transition to a pay-per-user model, but rather would completely dissolve the product, which nobody would miss.