Their exchange of letters on Morningstar's site is remarkable as much for Markman's tenacity as it is for Bogle's grouchy response. We can't resolve the debate here in one humble online column. This is fairly easy to prove mathematically. The results are in the chart below. The gap was even wider at the end of 1998.
Technology is probably one big part of the answer.
Out of curiosity, we looked at how closely large-company core funds correlated with science and technology funds. If there were a close correlation, we could assume that large-company core funds were stocking up on technology stocks. The table below shows how well various funds correlate with technology funds. But that's just one snapshot in time. But that might not be correct, either.