Practically, it doesn't matter like it didn't matter for Google that storage got many orders of magnitude cheaper. By the time training a novel LLM and serving it to a billion users is trivial in the way that providing 1GB of email storage is today there will be other moats. They'll have decades of user history and a monitization framework that will be hard to overcome.

Google is a viable competitor here.

Everyone else is missing part of the puzzle. They theoretically could compete but they're behind with no obvious way of catching up.

Amazon specifically is in a position similar to where they were with mobile. They put out a competing phone but with no clear advantage it flopped. They could put out their own LLM but they're late. They'd have to put out a product that is better enough to overcome consumer inertia. They have no real edge or advantage over OpenAI/Google to make that happen.

Theoretically they could back a competitor like Anthropic but what's the point? They look like an also ran these days and ultimately who wins doesn't affect Amazon's core businesses.