It's probably that, I grew up in the Midwest in a rural school district (outside the school district of a ~100k population city) - we had a 400 or so graduating class though. This was early to mid 90s, and it was pretty standard through the 80s too, at least for me. In the mid 90s I fell into a grunge group and they were a bad influence. Instead of getting bullied about being a nerd, it switched to that, and taunts about blowing my brains out with a shotgun (around the time that happened) were pretty common.

Edit: to add this perspective though, my wife went to school in a relatively small town (Rolla, MO) and also had a 400 or so graduating class, but she claims ignorance of any sort of nerd bullying and thought it was a TV trope only thing too. She graduated in 2002. Maybe something changed between those dates?

I went to two Midwest high schools in the late 70's early 80's, one was large (5,000 students) and the other was tiny (17 in my class). Both schools had bullies, but the smaller private school had bullies with behavior far in excess of the large public school. The larger school had bullies that would fight each other and protect some nerds they liked or knew, while the smaller school was not diverse enough, so the few bullies had nothing to stop them, and they went way, way too far.

I also didn't see nerd-bullying, coming from a 500-student-per-grade public school in West LA.

Admittedly, it was unrepresentative in other ways: one third Ashkenazi Jewish, one third Persian Jewish, one third mostly-white-and-Asian other, very high population of affluent immigrants. We were plugged in to American pop culture, but I think we were isolated in some senses. Little to no idolization of the sports teams, for example.