It might also be a sign that he had acquaintances rather than true friends. People who liked him for what he could do for them rather than just because he was him. And if he had an aptitude for learning, and found the stuff that was being taught at his own level to be easy, I can see him being drawn towards people a few years older who could teach him the more advanced spells that they were learning, provided that they were prepared to tolerate him in return. As a younger kid and tolerated prodigy he'd almost certainly be on the outer edges of the group though, which again would seem to fit with what we know of Snape as a loner who keeps his own counsel.

It'd go a fair way towards maintaining that chip on his shoulder. And also, it leaves him fairly rudderless once they all leave school and he's still there. I wonder how much the Marauders' campaign of taunting and worse might have escalated once his older pals who knew the more advanced hexes had all left and he was isolated?