Could your 1995 application be used by everyone on every system in a tap/click ?
Qt needs to be adapted and compiled for every platform, it takes time and efforts and it's not interesting. And making a good frontend in Java is hard, I can't think of any Java application with a good frontend.
Whole lot of sites suck on mobile, not all devices have the grunt
Write once run anywhere continues to be a pipe dream
Also none of my desktop apps track me or blast me with ads
This is just about the GUI too; I can install a CLI only setup, and do science, infrastructure, and avoid the web framework or OS GUI bloat…
There’s no one size fits all anywhere.