Alex let me state that I am referring to an average PC like I am typing on. It came with Vista and now is at Win8.1
It's on that kind of machine that I am saying TB won't ever "take off" on.
You say a lot of truth that I don't doubt and agree with. Like interfaces being sllloooowww to be adapted by the masses.
I agree with Sir Les in that USB was adapted quickly, and it's all over. Correct me if I'm wrong here, but aren't all cell phones (besides apple) today made with a USB port? It's not just on the PC anymore. It's all over! Not because MS wanted it, it's cheap and easy to implement.
And MS always has tried to make USB adaption easy.
Remember RamBuss. It was the better and faster memory. It just didn't take off because of price. Back then I remember saying I wasn't going to pay $200 for the same memory I could get at $100. What was the performance difference? Didn't effect me that much in what I wanted to do. I went with the cheaper stuff. This is another reason why I'm saying that TB won't be "taking off" on the Windows based PC anytime soon, if ever.