If we get to a point where interacting with browser DOM is comparably fast with Wasm, either through JS or with native APIs, then we could see Wasm replace React. That said, you're right that we probably won't see anything of that sort in the short term.
From a technology perspective, I think you're totally right that Wasm and WebGPU support is super exciting for game engines like Unreal/Unity. The ease of distribution could be a game-changer.
That said, I'm not super familiar with the world of game development and distribution. While web-based games have great distribution, the "best" technology or product doesn't necessarily win. Steam has massive power as an incumbent in the space, it does provides a useful service of facilitating discoverability for indie games, and there's definitely some scenarios where web-native games don't make sense [1].
Agree with sibling comment - the JS ecosystem has a huge momentum behind it and probably isn't going away anytime soon.
On the web, Wasm has currently found the most success with compute-intensive applications, since the JS <-> Wasm bridge is still pretty expensive. There are already some Wasm-based frameworks like https://platform.uno/ that work on the web, but things like React/React-native and Flutter have a huge head start.
More clearly: once Wasm interactions with the browser are fast, a new framework + Wasm could replace React + JS.