>It's proven in the sense that there is freedom to choose to write a native desktop client, and yet nobody does it anymore
There’s factors occluding this though I think-the JS/web stack has had millions of dollars of investment thrown at it by parties with a vested interest in seeing it succeed, so a lot of UX issues and friction points have been smoothed over as much as possible.
The wider native UI ecosystem hasn’t had the same investment, so I’m not surprised it’s superficially “easier” for devs to thrash out a UI with web tooling. Doesn’t mean the resulting application is actually any better though.