They said the same thing early in 7 and Vista.
The fact is the general population is not early adopters. Especially not at the OS level which usually is best to put on a new computer. Add to that the speed at which the new OSes have come out and the lengthening time people are keeping their PCs. People that bought brand new machines for Vista are probably just now in the contemplating upgrade phase. I bought a new machine right after Vista came out, but I put XP64 on it, eventually I added a HDD and upgraded it to 7, I’m at least 2 years away from getting rid of it, I’ll get 8 then... unless they’ve popped out another OS by then.
I think applications compatibility is something people aren’t going to want to deal with with 8 until as late as they possibly can.