OpenRouters moat is that a) everyone knows it, but not their gazillion competitors, and b) their API URLs and key are already configured in your OpenCode/Oh-my-Pi/whatever harness or agent you use.

As long as they offer stable services and do charge the same API prices as competitors (or even less maybe, since they have the most inference providers on board, because OpenRouters' prime popularity also exists with inference providers) you do not really have an incentive to go through the hassle of changing all your configurations.

What you just wrote isn't a moat at all. One is marketing, the other is a find/replace.

A "moat" is something that protects your product that is really hard to overcome. Like a migrating your database to another vendor, for instance... Or finding your friends and the people you follow on another social media service.