He's also wrong. There's 650b Mtn bikes now. It's spreading. I think it will remain a niche product, but so what? I don't worship at the altar of mass manufacturing.
I have said it before, I will say it again. 650b is terrific. I gambled that Grant was right, and won. My wife loves her bike to death.

We both owned Bridgestone XO bikes way back when. So we've tried going that route with 26 inch tires. Ain't da same ting at all....