The slowness is a feature, not a bug. It gives your brain time to chew on it a little bit, digesting the information and storing it away instead of just copy-pasting.
Speed-hacks like shorthand and stenographers' machines are for copying exactly what was said, not consuming and understanding it. I would be very surprised if there were not very old studies moldering in a paper journal somewhere investigating the information retention of secretaries / stenographers compared to "naive" note-takers.