The unabridged audiobook is just under 24 hours. 16 hours seems short, but not terribly so.
You can read those masterworks at a superficial level and they’re usually somewhat rewarding. Or you can read Dostoyevsky while deep diving on Russian history and get a notably different experience. But it takes a lot longer.
1: https://www.theatlantic.com/entertainment/archive/2013/08/th...
Overanalysing it kills that pleasure and atmosphere. That is not reading, that is doing seminar.
People want 1.5 speed because that's what gets the narrator back to a normal speaking speed.