I see. I did not really follow the literal sense of "utopian". Such a high bar doesn't really exist for software. Just from a philosophical point of view, such a thing can arguably not exist. So I honestly didn't think anyone was actually taking that at face value.
But, to just focus on the arguments you had on Linux. Android is only a drop in the water in terms of Linux kernel usage. And we have every reason to believe they chose Linux based on its technical merits. It actually works pretty well for what an operating system needs to do. The top 500 supercomputers, worth billions (the fastest one alone cost 1 billion) don't pick Linux because it is cheaper. They pick it because it does what it needs to do, fairly decently. The NT kernel has a bag of decades old shit stinking up the place, so that's a no go. And MacOS forked Unix is not licensed to run on anything non-apple branded, not that that would matter, since there would be zero incentive to do so.
The argument presented that there is no open source software that is better than the commercial equivalent, is what I gave counter examples to. Which is demonstrably easy to argue against. Which I have done. You wouldn't want to use anything other than Linux for a supercomputer. AWS and GCP run their systems on Linux.