Boy, that's quite a lot to discuss.
Looking at your third paragraph, there's almost nothing there I'm interested in doing. I'm not worried about malware; I haven't had an infection in the over 20 years I've been running Windows, and good anti-malware software is free these days. While drivers may not be in the kernel, Windows does a pretty good job of finding them on the web, so they're more likely to be newer than the ones in the kernel; and why take up hard drive with drivers you may never use? I don't have multiple users. I believe you can legally run W8 from a flash drive (although I don't plan on doing that or running W8 so I can't confirm). I doubt many average users are interested in booting multiple OSs, or are interested in overriding the 'safety' features. Obviously they don't care about walled gardens; see the popularity of the iDevices.
As to customization, most of what you've listed are customizations to the desktop or apps, not to Linux itself. My comment was in response to those who claim open source programs are customizable because the user has the source code. My point was regarding those users inability to read, understand, alter, and recompile that code.
Don't get me wrong; I think Linux is a great OS. I understand how you feel, but I don't think the average schmoe is any more interested in getting the most out of his computer than he is in tuning his engine or making his own clothes. There's no motivation for me to bother replacing Windows, finding replacements for my existing applications, putzing with an emulator for those apps that don't have Linux counterparts, etc. It already does what I need (or want, if you will). At home (as opposed to at work), I'm interested only in USING my computer with as little effort as possible. I drive an automatic transmission for the same reason; I'm aware I'm sacrificing some performance, but it isn't worth it to me. I suspect most home users feel the same way.