I know it's cynical to say, but if that's the case, where are all the big budget 3D triple A games in web browsers?

Still a long way to go, and I remain unconvinced that web browsers are the best place to play those kinds of games, especially on mobile. Even with the ability to hide the web browser chrome by adding a web app to the home screen, abstractions upon abstractions upon abstractions without proper access to system frameworks that the browser doesn't have access to (like ARKit, HealthKit, etc.) low-level APIs (like Metal, as opposed to WebGL) just get in the way of what game developers are capable of now.

We might get there in the future, but not yet.