The Piazza post isn't publicly viewable, but I'm surprised you had this experience at MIT. The majority of classes I took had a ton of materials online and there were few instances where I felt I needed to go to class purely because of an attendance policy or a reluctance to share materials. Office hours are designed to be 1 on 1 for educational reasons, but other students collaborating at office hours (or outside of them) was encouraged on psets. I wouldn't expect any of this to be worse post-COVID either. Maybe a course 8 issue? But I'd be sad to hear this was the case now with 6 or 18 because it certainly wasn't in the past (and MIT was way ahead of peer institutions on this historically, in large part due to OCW)