I agree with that; I'd take an Elvin Hayes, for example, anyday of the week over anybody in this draft. I guess it is skill, or a lack thereof, that has made the "classic" center obsolete, or M.I.A. in this current era. But so many of them are so thin, relatively speaking, compared to "classic" centers of the past. Like you don't see anybody with an Hakeem body, or a Ewing body, or a Shaq body, or a Rik Smits body, for that matter. Dwight is the obvious exception to the trend, and it looks like Andrew Bynum has potential, but otherwise, the physicality isn't there either. Honestly, Lopez and Hibbert look like a couple of stiffs out on the court, and I think their problems are as much of the physical nature as of skill.
"Classic" centers of years past could easily still dominate in the NBA; while they may not have been as mobile as the "centers" of today, they were nonetheless athletic and understood how to use their size to their advantage and not spot up for a 10 footer instead of honing their post skills. I think skill is a big part of it, but there is some biology mixed into the equation as well.