In my experience with the many educational services and communities that do summarize the important content, if you do simply read/listen to the hyper condensed

In my experience with the many educational services and communities that do summarize the important content, if you do simply read/listen to the hyper condensed version of 4+ hours a week of lecture you will most likely need to spend that same amount of time saved reviewing to absorb the material if it is anything past the most basics. What the most basics are will vary between people but at a certain point in your learning the time spent thinking about what you're learning simply becomes an important part of the learning process. Personally I find the "chit chat and hollow conversation" far more pleasurable than spending those hours alone reviewing notes, obviously with the caveat that most of the discussion is related to the material at hand in some way