Qt does exist. It's not difficult.

Qt costs serious money if you go commercial. That might not be important for a hobby project, but lowers the enthusiasm for using the stack since the big players won't use it unless other considerations compel them.

QT only costs money if you want access to their custom tooling or insist on static linking. We're comparing to electron here. Why do you need to static link? And why can't you write QML in your text editor of choice and get on with life?

Depends on the modules and features you use, or where you're deploying, otherwise it's free if you can adhere to the LGPL. Just make it so users can drop in their own Qt libs.

I'm sure microsoft and slack have sufficient funds for a commercial Qt license.

...which is the same as Flutter. Both don't use native UI toolkits (though Qt doesn't use Skia, I'll give you that (Flutter has Impeller engine in the works)). And Qt has much worse developer experience and costs money.

Qt costs money if you for some reason insist on static linking AND use all the fancy components, the core stuff is all LGPL.

Anyway it does look native and it is way faster than electron, which also doesn't look native so I don't understand why it's a problem for Qt but not for electron.