I've proposed an idea several times that I think might resolve this situation, but it's never received any real uptake and I can see some serious issues with the approach.
Instead of building a "inner system" (https://en.wikipedia.org/wiki/Inner-platform_effect) where the browser uses HTML, CSS, and Javascript to create interactive applications, or attempting to make a sandboxed and highly limited execution environment (WebAssembly), browser tabs should be Virtual Machines- in the sense that VMWare, KVM, and HyperV are VMs, not in the sense that some language runtimes are VMs.
Think about it: every tab on your machine could be its own little machine running a full stack and rendering the output to a framebuffer (the tab window content). It provides precisely the sandboxing and virtual IO that existing VMs have already implemented and optimized.
But of course, if you do this, you don't actually need a browser window with tabs: you just render the application to a standalone window. But then really what value does the browser provide, other than giving you some convenient runtime for accessible web resources? So just put the browser runtime in the operating system and host applications within virtual machines. Nothing stops you from building applications using web frameworks- you can still use javascript, HTML, and CSS if you want, within or seperate from existing high quality graphics application frameworks (like Qt, GTK, etc).
Those reading carefully will note this is exactly what (some) operating systems have been capable of doing for longer than the WWW has existed, and all major operating systems now support this natively (KVM, HyperV, Apple Hypervisor) and they also all embed full browser capability in native libraries. The main issue I see is that there are now 2 or 3 hardware architetures (x86, arm, risc-v) and a VM does not directly resolve performance issues of cross-arch translation, so devs would still need to produce binary packages for 2-3 archectures to reach the level of cross-OS compatibility that browsers currently support.
I work frequently with Qt and it's amazing how much better it is for building powerful, complex applications that have long term support.