From their site:
OpenAI is a non-profit artificial intelligence research company. Our goal is to advance digital intelligence in the way that is most likely to benefit humanity as a whole, unconstrained by a need to generate financial return.
The money quote is at the end, literally—$1B in committed funding from some of the usual suspects.
The whole point of open-source is distributed oversight. It also sounds like they will use the Apache license or the MIT license so there nothing forcing them to publish everything should they decide that isn't wise in two decades.
Good. I was worried for a moment that our new artificial overlords will transform the whole universe into zillion tiny copies of GNU GPL.