Where do you think all the VC and angel money is coming from? Banks and pension funds and investment firms are almost certainly funneling money into these things, we just don't get to see it because it's being done on the private market.

The very thing that makes everyone comfortable with this bubble (that it's mainly "private" capital) is the scariest part. Last time, you could mostly tell when grandma's retirement fund was betting the bank on social networks for dogs. This time, it's all on the down-low.