There's a comment somewhere on HN from a Slack dev who was the one responsible for moving away from platform-specific webviews to Electron. The core reason is that Electron is the same on all platforms it ships on, generally speaking.

Platform-specific views simply aren't. For simple applications they might make sense, but at a certain point devs just want the shit to work. Electron solved that.

I do agree that LLMs & co should contribute to reversing this trend, though. I don't really see why you couldn't try to ship (true) native now.