Even if web rendering is the best technology possible, there's still plenty you could hypothetically optimize, like replacing the Javascript with native code, or cutting out unused features to get a smaller download.

Ultimately, Claude having limitations is an issue. They can't just point it at the code base and ask it to make it faster.

You've basically described Flutter and Jetpack compose(for desktop). The problem really does turn into effort to pay off, even if we stayed with JS and the rendering engine, figured out a way to compile JS into native code and completely stripping all of the unused functionality and doing the same thing with the rendering engine. All of that would need to be made, it's not like electron apps literally crash you machine. You have metrics, hundreds of millions of devices running electron apps at a daily basis. Unless you make your own company, I don't think anyone can convince their leadership to take such a decision.