First of all, that's not true. Most players play several tables at the same time against the same player, up to four heads-up. That's something like 600 hands an hour in HU.

There's little heads-up play in live games, other than at the end of the tournament, and the stack sizes are completely different. These are not tournament players, they're heads-up specialists. They most assuredly play online the majority of the time.

Second of all, the computer doesn't read the human players, why would it matter? It's all up to actual strategies at that point.

Not really. Online poker is much more popular. Plus the computer doesn't have a camera either. You have to deduce if your opponent is bluffing through the plays he/it is making.