He was referencing the limitations of copper POTS, of course. But I still found it funny (if I recall correctly, it was printed side-by-side with his debunking of the 'you only need so much ram' quote).
Higher speeds werent possible until moving to digital lines (64k for IDSN, single line, 128k for dual). DSL upped the anty, pushing to 1-3 Mbps in my area. Cable really pushed it when I could get 15 Mbps vs best available DSL in my area at around 3 Mbps.
Today, I have around 200 Mbps over cable (gigabit is available), best DSL in the area is still around 25 Mbps. Fiber is not available yet, but AT&T is running fiber, but 2 years in, still not an option and they haven't published pricing/speeds for the area.