We should have listened to Hyatt back in 2003-ish when he basically said of XUL, "it's never gonna be great on *nix or Mac but it's good enough on Windows." Because of solid desktop horsepower growth over the 2000s, we were able to make XUL go for the three desktop platforms pretty well but it should never have gone to mobile and replacing it with a native front end was absolutely the right thing to do, despite the pain.