I believe you have proved my point that you're speaking of very niche examples. Even Sublime Text won't load a 100GB instantly on a normal machine. And I consider it a very well-made app. While of course there might be apps that will load such files instantly, they are highly optimized for such a task. My point is that Qt is more than enough to replace all those Electron, and other web-based apps, while performing as good or even better than native apps.

At the end of the day, Qt can also be just a wrapper for your highly optimized engine - for example, NotepadNext[1] is using the very performant Scintilla engine while its UI is written in Qt. From my (unscientific) tests, it's even vastly faster than Sublime Text.

BTW, I'm not saying that rendering and creating your own UI is always a bad idea. Many people do it because it's fun and challenging, or to push the boundaries. That's what Vjekoslav Krajačić is doing with Disk Voyager - writing a file explorer in C from scratch[2][3]. But for many people, that's too much. I believe Qt C++ with QML is the best combo for most people, for most applications.

[1] https://github.com/dail8859/NotepadNext

[2] https://diskvoyager.com/

[3]https://www.reddit.com/r/SideProject/comments/103b9fy/disk_v...