The thing is, it appears that data was accessible. Perhaps they didn't sell it, as such. Perhaps companies paid to put a game or quiz on Facebook and they were given info on the users who used the game or quiz.

Or maybe Facebook put the games/apps up for free and just gave the data away?

I dunno, but "We aren't in the business of selling your data. We just gave it away." isn't a great message.

Businesses set their own model and can change it whenever they want.

Tesla can start selling killbots, guess what, that probably isn't going to happen

Ok...?

The point is that companies like Tesla can change their business model at anytime and start selling something new, like they did when they started selling battery packs in addition to cars.