There's an argument to be made though that hyper-targeting helps niche or smaller businesses more than a P&G who has to run a larger campaign so the IRR could drop more for smaller businesses than a large company on Facebook specifically?
Facebook & co are just destroying all these small businesses (local newspapers, local magazines, billboard companies, local news websites, whatever).
The internet has changed how people consume and get new information forever and that won't change anytime soon.