Serious question, Are the days of native applications UI (be it Windows/Mac/Linux) are numbered? Does it make sense to develop a native application now days? (games and heavy CAD software aside)
The pattern that Electron and such are continuing is that they do a base set of things well, but then integrating with OS services is non-existent, even though for any given OS it's relatively trivial.
Don't be too impressed that it can run anywhere at acceptable speeds; Java solved that 20 years ago.
Rather, it's more fundamental: as you add in all the functionality provided by various OS's you have to model all that functionality and it has to be comprehensible to your users and maintainable by you.
Some of that functionality is flatly contradictory and much of it is peculiar to a small audience. You can theoretically engineer around it, but in practice, you won't be able to maintain it and no one will want to use it. That's an intractable problem.
That's why I think cross-platform framework authors have consistently been leaving various bits of functionality out for decades. They'd rather deliver "second class" applications than nothing at all, and that's a smart trade-off.
But that does leave a lot of space for native apps.
When you think about it, iOS and Android apps are desktop apps (in full screen mode), not browser apps. And they may be more popular than web apps, for now (though I hate the toll imposed on them).
Maybe someday soon, you'll be able to click on a web app and turn it into a desktop app, with better native platform integration. That might be a reason to stop desktop development.
I know for myself (15-ish year Java dev), even if software I'm writing will only ever be used on my local laptop, if I need UI I'm likely to do a Spring Boot app with a web frontend and Bootstrap.