What's the alternative? I doubt even someone as big as Samsung will be willing or able to develop their own alternative OS (atleast one that can actually grab marketshare enough that critical apps get ported), and I can't imagine them wanting to hitch their wagon to the Linux alternatives.
Why would they be forced to develop their own OS? They could just license this theoretical future proprietary Android OS.
> I doubt even someone as big as Samsung will be willing or able to develop their own alternative OS
Huawei pulled it out with HarmonyOS (I don't know how good/bad is it, and if it'll have staying power, but other companies are putting in the effort)
PS: btw, Samsung already had its own, non-Android OS with Bada (of course, developing a new OS is only the first step, getting it to be successful wouldn't be easy)