Sam Altman on the reasons for the Sora decision: 'We have a few times in our history realized something really important is working, or about to work so well, that we have to stop a bunch of other projects. In fact, this was the original thing that happened with GPT3. We had a whole portfolio of bets at the time. A lot of them were working well. We shut down many projects that were working well, like robotics which we mentioned, so that we could concentrate our compute, our researchers, our…