The ability to have these conversations would have increased my velocity pretty significantly. There doesn't even need to be real-time communication: the ability to email someone with heavily contextualized questions, knowing that they've been working on the same content recently, would be incredibly valuable.

This is especially important IMO. Used to be when I studied more actively, whenever I'd get stuck and someone I knew happened to be online and also studying the subject (or had mastered it), I'd just ping them up on chat.