The two major commercial producers of proprietary operating systems are basically giving away their operating system at this point. Free Linux distributions offer basically the same functionality for most users; the only things preventing migration from one OS to another are existing applications. For non-gamers, that's often moot, because the world exists in a web browser now. Yes, there are other applications causing OS lock-in too, but they're mostly on the business side, not the consumer side.
There is still plenty of money to be made from enterprise operating systems, but the innovation there is in a totally different direction than what consumers would find valuable.
Example: Linux containers are great! But who's spending the R&D money to make them a viable way to distribute games? There's plenty of work being done on containers and graphics chipsets for ML applications, but not for consumer use.