what kind of shitty parents just drop their kids off at their high school football or basketball game and then just leave to not watch them play?

I was in marching band (so I played at all the games). Is that not normal?

I guess it's just a generational thing, but my late Gen X mother was simply busy. Army drills twice a month will do that. I also concur with other responses that these were all social events anyway, so it's not like I was yearning for Mom to be there.

At a typical US high school, not very many of the students are actually playing. For most of them, it's mainly a social event, something to take a date to, or a time to hang out in the bleachers with peers.

Even if you have one child playing (or on the bench, or in the band, or cheerleading) and have come to watch, your other similar-age children will likely not be interested in sitting with you. They will want to sit with their friends, and rightfully so!

maybe because I don't live in a car-centric country, but I would just bike there myself with my friends, play, and bike home with my friends. From I was a kid until end of high school. Parents would often come to watch, but not always, and the fun was being with my friends anyways so it didn't matter.