1) Most users do not need or want root access to their mobile phones or even any of their devices. There's a reason that in UNIX land users and root are separate things.
2) If you really want root, you CAN get it. Yes some manufacturers make it harder than others, but that's again because 99.99...% of users have no need or desire for it, and making it easier for the tiny, tiny number of people who want it is not a worthwhile investment.
Now you can argue that their efforts to make it even harder to get root access are shitty, and I won't disagree with you, but nobody's forcing you to buy these devices.
3) DOS/Windows 95/etc. are not awesome. Pretending it's awesome just because it was "open" (no permission system) and "backwards compatible" (debatable in many cases) is stupid. You're letting nostalgia or your hatred for "closed" systems bias you. Just because thing A isn't perfect doesn't make thing B great. Both thing A and thing B can be shitty, or they can both be good.
4) Linux is fucking everywhere in 2013. It owns the web. It is on most mobile phones. Even Apple devices are running a fork of BSD. So, how is this a Pyrrhic victory? Just because it's not exactly what you want? I'm so sorry.
There's a, frankly, revolting tendency in geek culture to be absolutist. That if something is not 100%, exactly, totally, purely aligned to your personal vision it's fucking garbage, or worse, evil and bad. This is childish and it's time to grow up.