What the hell? There's no sign that Musk and Altman have read Bostrom, or understand the concept of an intelligence explosion in that interview.
It seems that they consider a soft takeoff more likely than a hard takeoff, which is still compatible with understanding the concept of an intelligence explosion.
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.