If Sama feels the current players are not doing enough, it seems entirely in line with his publicly stated and often repeated goal of advancing AI, that he would try and move things along. That's just extremely consequential execution.
This would most likely have been a pure grift play, finding some stupid money and using his position at OpenAI to convince them to invest in a doomed proposition.
Best time to start was 10 years ago…
Starting from scratch would make sense if Altman personally were some kind of chip design savant with unique insight to the problem domain, and he definitely isn't that. Alternatively it makes sense if had nothing to do with saving OpenAI from the compute bottleneck, and was another one of Altman's Worldcoin-like grifter schemes.
You either assume transformers are here to stay and somehow get an edge over Nvidia and others trying to do the same or you make a huge variety of bets on whats next.