Isn't the whole point of these competing stacks not to provide an alternative to Android but to provide an alternative to all phone OSes? The idea being that yo

Isn't the whole point of these competing stacks not to provide an alternative to Android but to provide an alternative to all phone OSes? The idea being that you can write your application 'once' and it will be available on Android and iOS (and, as a comedy option, Windows Phone I guess)? If you look at these toolkits in that light then their existence is justified without it being a nail in Android's coffin, so to speak. Not that the underlying tooling can't be better, but devs are moving towards cross-platform toolkits precisely because they are cross-platform, not because Android is terrible.