Kinda the opposite. Openrouter exist and you can host any model, but even within the model there are bunch of params that affect how good is the output you get.

And while most hosts list these upfront, & you just gotta be smart enough to request with specific requirements, I've heard there are still good reasons to just stick to a list of trusted hosts sometimes, I don't really remember what was the issue, quantinizastion level that they aren't honest upfront maybe.