"best" is subjective, but I do think the industry will eventually converge onto an architecture that is significantly more cost effective than current state of the art. Regardless of who is first to market, everyone is incentivized to continue down this path with their research on improving LLM performance.

While the first mover advantage exists, I don't think it's a sufficient moat in the long term.

OpenAI's moat is the high cost of training as you mentioned but this might be obsolete in a few papers down the road.

They themselves realized this by trying to turn it into a platform but I don't think it's enough.