That's just one obvious example. As for your analogy, that's like saying people were already doing a great job communicating via phone and email, what's the point of IM, twitter, or social networks in general?
You're vastly underestimating the potential value of access and storage of more and more precise behavioral data combined with the innovation of a startup vs the stodgy, uncreative, stubborn ways of both old world telecom and finance corporations. Back then, even with access to people's purchasing data and past addresses, I would have had to do a lot more work and ask for larger increases to our budget to figure out people's relationships as well as non-purchasing behavioral data aside from traffic. Now I can potentially have access to people's preferences to stuff as opposed to just guessing. Today it's much easier and cheaper.