I should clarify, by private cloud, I mean a few custom designed servers running open stack or something, and DC I mean some built up "pod/rack" design you might colo. Ether way, I mean end to end, I was just trying to account for colo and on-prem (two sigma, for example, have a small private cloud in their office that's quite well architected.)
My guess is that he's talking about design custom equipment for efficiency and performance. It's a movement akin to moving from EC2 to in premises: if you're big enough, it starts making sense to custom build, often with in-house development.