Earlier quoted context omitted.
Apple conceded defeat and we have different interfaces on each device class. Apple hasn't conceded defeat. Every release of MacOS becomes more and more like iOS. Apple keeps releasing tools, such as Catalyst, to make it easier for iOS developers to get their apps to run on MacOS. Apple is very much pursuing convergence between iOS and MacOS, to the latter's detriment.
You can run any app on any platform. It's just going to be a shit experience. Apple want you to get 80% of the way there, then do the last 20% of tailoring it to the device. There isn't some magic unicorn toolkit which can do that last 20%.
In practice that never happens. Developers make their mobile app, use the automated tool to make it into 80% of a desktop app, hit the publish button and proudly advertise, "Hey, look, we have a desktop app now!"
Maybe it's fine for Apple and Google to ruin their desktop UIs like that. Maybe they don't care, or, more likely, they think that catering to the vast majority of users who are on mobile is an acceptable tradeoff for alienating the few of us who still prefer desktops as their primary computing device.
But why does Linux have to tread that same path?