Many years ago, I spent 20 years using Smalltalk to try and realize the "cross platform" dream, just between MacOS/Windows/X11. You can do trivial stuff easy, and in the end, it only goes so far. I concluded it's not really possible. The Java guys then tried. And had similar results. As have many other toolkits with varying degress of success. I've done Flutter, and again, same conclusion. I won't say that someone won't pull it off someday, and I won't begrudge their success--I'll even cheer them on--but my experience won't allow me to personally bet "this time will be the time finally". but i'm happy to be proven wrong.