I was listening to Greg Low's podcast SQLDownUnder show 13 with Bill Graziano, and my ears pricked up when Greg made the comment that most of the consulting he does is on improving performance, and posed this as a question back to Bill as to why...actually, I became interested because Greg mentioned that developer knowledge could be to blame - that's me :-)
The first part of Bill's answer, and the part that stood out, was:
"...[I]t's easy to grow data at a rate that we never could before. Back in the 80's...it was just so much harder to generate data with...