The car configurator demo loads a 117 MBytes WASM blob and then hundreds of tiny files between a few hundred bytes to a few KBytes, both extremes are worst case for a web application, it's quite hilarious really.
The demo didn't finish loading while writing this comment, and it doesn't look like the loading of those tiny files will ever end...
In my case, several of the WebGPU demos on https://simplystream.com/demos fail (while keeping on falsely showing "Loading") with the error message (in DevTools):
"WebGPU requestDevice failed, trying low spec DOMException: Failed to execute 'requestDevice' on 'GPUAdapter': Required limit (64) is greater than the supported limit (32)."
I can't imagine it being good in a web scenario where you can't even precompile.
I have higher hopes for the web people (like PlayCanvas, Babylon, threejs, etc...) writing a proper WASM game engine by "scaling up" their experience of building browser rendering engines, than the traditional "native game engine" people "scaling down" to web requirements (especially when it comes to time needed to start into the game - the entire asset loading system of native engines needs to be rebuilt from scratch for this).
In regards to downloading assets, we've built out an asset streaming system to address this. It allows you to dynamically load in just what you need, when you need it, while everything else that isn't needed right away can be fetched at runtime.
And your assumption is based on what exactly?
WASM + WebGPU don't magically make the whole game, its assets and the engine it uses appear on your computer.