Ironically, “Web Excel” doesn’t use any of them. And if you asked someone who can create Excel to implement it in a webpage, they wouldn’t probably even think about these frameworks seriously.

The real promise of these is web forms with a little interactivity. Anything more complex and you start to fight with it to drop back down to the level where it’s manageable.

React is a little bit painful and massive overkill for web forms actually (compared to other approaches).

It’s the fighting with it that’s the issue; my experience is that a lot of devs go in to “force this stupid framework to work” mode and blow up tasks that should be 10 lines of code with no edge cases into 50 or 100 which “mostly works, good enough.”

React is by far the most adopted framework for desktop-level or near-desktop-level web applications.

That's been a complete opposite of my experience. I'm now on my second full-fledged IDE that is built with React, and I'd take it over any other tech.

According to LibJS Detector, Excel Online is using react.

Not sure which web-based spreadsheet app you're talking about, because there are many that do use these frameworks. Here's a PS/AI clone built with a Svelte frontend: https://graphite.rs