There is definitely a lot of truth in all of this.
I've given Ubuntu a fair try many times, and I'm experimented with some other distros of Linux. I use and love Ubuntu Server for running a personal web server because it's free and it does the job well on minimal hardware. I started out my server using Linux.
But on my desktop, it's much different. I've always used Windows and probably will continue to use Windows for a long time. The reason is simple. I've always used Windows, it works fine, and I personally like it. Sure, it has it's quirks. But so does Linux, even more so than most hardcore Linux users will admit.
Especially for those who know little about computers, there's no reason to switch to Linux. The world uses Windows and it works for them. Without a huge incentive to change (and simply being free isn't really as influencing as you might initially think, since Windows usually comes preinstalled).
Whenever I talk to my friend, who has completely switched from XP to Ubuntu, I can't seem to explain to him why I have no desire to switch. Sure, Ubuntu is great for a free, open source system. In fact, it's incredible for that. But in my opinion, it can't compete with Windows yet. It's not really Linux's fault either. Things like hardware support are lacking (though getting much better quickly) in Linux, but they are strong Windows simply because hardware manufactures write drivers for the OS that is used by the majority of people. I'm happy with Windows as it is (I run XP, by the way, not Vista). I'm looking forward to Windows 7. And I simply don't have a good enough reason to switch to Linux.