Last spring I made a little tool called Tipsy Turtle. It doesn't look like much, but I'm happy with it. At least it looks like a native Linux app, thanks to its use of Gtk3 on the back-end. Lacking some niceties, sure, such as stock icons, but otherwise fully functional, with theme support and everything:
For various reasons, that are too long to explain here, I'm now trying to see what Tipsy Turtle might look like in an alternate universe, if it was made with a different language and libraries. I came up with something quickly enough.
It's just a mockup for now, written in C, with a little-known library called XForms, that received its last update in 2014; it's still included in most Linux distributions despite that:
Looks like something out of the 1990s, doesn't it? Kind of is, really. Rough and squarish. No gradients in sight, and probably no accessibility support. Not something I can proudly distribute to a wide audience.
It also has personality. It looks like something, that's just it. Those buttons pop. You can tell right away where you can click and where you can type. I can read those labels without glasses!
Sure, I had to tweak the colors and fonts a little. But I could! Modern toolkits make it all but impossible. Even though it would hardly conflict with theming. This isn't to help users, make no mistake. This is the Apple design school at work. Everything has to look flat. Clean. Bland.
Don't think, buy. Buy the new version, same as the old version except twice as bloated and expensive, and feel special because we're gouging you.
And open source developers bought into it wholesale. I have nowhere to go.