On MacOS is much better. But most of the team either ended up with locked in Mac-only or go cross platform with Electron.
You don't need to use microsoft's or apple's or google's shit UI frameworks. E.g. see https://filepilot.tech/
You can just write all the rendering yourself using metal/gl/dx. if you didn't want to write the rendering yourself there are plenty of libraries like skia, flutter's renderer, nanovg, etc
Even though OpenAI has a lot of cash to burn, they're not in a good position now and getting butchered by Anthropic and possibly Gemini later.
If any major player in this AI field has the power to do it's probably Google. But again, they've done the Flutter part, and the result is somewhat mixed.
At the end of the day, it's only HN people and a fraction of Redditors who care. Electron is tolerated by the silent majority. Nice native or local-first alternatives are often separate, niche value propositions when developers can squeeze themselves in over-saturated markets. There's a long way before the AI stuff loses novelty and becomes saturated.