Actually Linux (and similar copylefted OSes and libraries) doesn't qualify as part of this because you can legally uproot support provided you retain copyleft.
Theoretically, but not practically. If you buy a Linux program, you are "locked in" to Linux, at least as much as if you buy an iOS app or a Windows program it ties you to those systems. Even open source programs are locked in until they are ported, just like any other system. If you download VLC or Battle For Wesnoth for the iPhone, you are in the exact same boat.
Not true. You're allowed to view, modify, and port dependency code in open source OSes.
Many other platforms are becoming increasingly difficult to emulate or otherwise provide support to applications outside of the original platform. PS2 emulation is dead-in-the-water without an encrypted dump from a real PS2... Apple sues unauthorized vendors of Apple products.
That's a wholly nonsensical article. When you run software, you make a copy as affected by copyright law. Mac users get a license to run Mac OS X on a Mac. The notion that every Mac user is in violation of the DMCA is ludicrous. How you came to the conclusion you did is beyond me.
Tell that to the judge who ruled in Apple's favour or Apple's lawyers who posed that argument. Fact of the matter is, a program making a copy of itself from a hard-disk drive to RAM is in violation of the DMCA.
"Conversion, fastidious Goddess, loves blood better than brick, and feasts most subtly on the human will." -- Virginia Woolf, "Mrs. Dalloway"