Most doctors would absolutely love to spend way more time with each patient, but they're not ultimately the ones in charge. The hospital administrators are absolutely intentionally overbooking their doctors to maximize profit. That's not even a thing they'd disagree with if you asked them. That's just how for profit healthcare works. America having a shortage of healthcare professionals came after that, because most people don't like working under those conditions.

Ehhh... Doctors have a hell of a lot of administrative paperwork for each patient they have to do. That's where the actual time goes. At least for Emergency Department doctors. I can't speak to private practice docs.