Given how many companies are being acquired now just for the team to be added to large-company engineering teams, is this really surprising? How many co's have Google, Twitter and Facebook acquired just to toss the idea aside and integrate the dev team? This way Y Combinator can get a few really good people (who work well together!) for fairly cheap and flip them to a larger company. It's quite a decent short-term strategy and the cost of acquisition may even be less for Big Co™ than the recruiters they might normally try going through.