One that prevents you from competing, but not most larger tech companies.

If you think if it like any other product, the picture is clearer.

A startup invents a widget whose production costs are somewhat high, but there's no patents/etc. So all major players could invent their own. Where's the value? Just in the sale to a major player.

I hear you. What do you think of the time/expertise/tooling it takes to train these models (and that's it's an iterative process and openai has a significant head start). This strikes me as more than a 'first to the gate' advantage (but perhaps less than a traditional moat).