You're kind of fighting against Qt or GTK when you do that. Qt and GTK have their own widgets. React Native is more of a framework that uses native toolkits to begin with, so it starts out with much better alignment with platform expectations, and has better interoperability with platform features.
> There are not multiple "native toolkits" on Windows or macOS.
I'm confused by this comment. I don't know what kind of point you are trying to make here, or what you are responding to.
> So basically, you're denying that it's possible to do excellent cross-platform apps at all. OK. I'm not sure I agree with that, but it's a position.
Yeah, let's dial the "it's a position" condescension back one or two notches.
When I said, "Different platforms are just slightly too different from each other to make it work well," the "it" refers to cross-platform toolkits like GTK and Qt, which provide their own widgets. This explains why so many people use Electron and just embed a web browser (let's say "fuck it" and make one UI inside a big window), or choose to use something like React Native. Maybe I'm drawing too fine a line here--I think of Qt and GTK as cross-platform toolkits, I think of React Native as a framework without the toolkit parts, and I think of Electron as some kind of cross-platform box that you can something inside. I'd rather not talk about the definition of "toolkit" or "framework" because the definitions are not material.
Qt is a big honking mess, and GTK is worse. Speaking as someone who has written apps using both, and fixed UI problems in people's open-source Qt and GTK projects.