> But the problems we’re talking about are far broader
No. You're fundamentally misunderstanding the broadness of the web platform.
On a broad platform even niche use cases are common. If I'm developing an application that will be used by 50 users then none of your concerns are relevant. I know my user base and I know what I need to achieve.
If compiling to WebAssembly and using canvas makes the most sense then that's what I'm going to do, especially if it means I can make use of existing business logic.
It is precisely the broadness of the web platform that makes this possible.