The proportion of the population that is actually good at retaining information is too small to sample, but I'd bet that they don't take notes on average.

Retaining information shouldnt have anything to do with how you ingest it. You need to have a place to put it. This means working with that information. Relating it to other pieces of information, imagining examples in real time, or, more formally, writing the shortest program you can that outputs the thing (modulo the constraint that you write it out of other programs stored in your head).