I think faang and the like would probably crowdsource it given that they would—according to the hypothesis presented—would only have to do it every few years, and ostensibly are realizing improved developer productivity from them.
I don’t think the incentive to open source is there for $200 million LLM models the same way it is for frameworks like React.
And for closed source LLMs, I’ve yet to see any verifiable metrics that indicate that “productivity” increases are having any external impact—looking at new products released, new games on Steam, new startups founded etc…
Certainly not enough to justify bearing the full cost of training and infrastructure.
And that’s assuming you already have a lot of the infrastructure in place.