Between family, my full time job, side projects.. I had no choice but to listen to some of these books as Audio books.. I ended up pretty much listening to 25+ audio books this year.. the only way to make the content stick is to:
1) take a ton of notes
2) do exactly as you say, rewind over and over until you can mark it down.
These are the next few features I want to add to this thing, taking notes and rewinding quickly and bookmarking snippets precisely because of your point that audio requires a little more work to retain. Still worth it though, I would have never been able to read that many books this year given how busy I am.
Ultimately I will concede that it will never beat reading, but when we have no time or are commuting? This, in my opinion, is the next best thing for busy people.