The incompatibilities just moved to different places, where the focus of development and competition is. Taken collectively, the various core services of mobile devices, desktop OS's and browsers interoperate very poorly across vendors. Think about stuff like identity, auth, sync; even very basic cases - e.g. user using a couple of Apple devices one of which is a macOS laptop where they run Chrome - are an incomprehensible mess of incompatibility to most non-nerd users.