I went to a school about your size, just more recently. My graduating class was somewhere in the mid 700's. There was more than 2 levels of math and science. Granted there was only two with the same name, AP calc 2 and calc 2, or AP calc 1 and calc 1 etc. but not everyone even made it to calc1. By 12th grade students were spread out into any of the following math classes: Algebra 2, Algebra 2 AP, Pre-Calculus, Calc 1, AP Calc 1, Calc 2, or AP Calc2. Thats 7 different "senior" levels of math in a single highschool. If you're goal is just to graduate then Algebra 2 is where you finished. Depending on your academic ability and how far you really wanted to go you could be as much as 7 "levels" ahead of that by the time graduation rolled around. Thats not to say that you'd have to take the other 6 to make it to AP Calc2. The highest "path" you could take would look something like Alg 2AP -> Calc1 AP -> Calc2AP. But in order to do that you'd need to start Alg 1 in 7th grade (Alg1 in middle school was split into two years taking 7th and 8th grade to complete allowing you to go straight into geometry/trig your freshmen year in highschool, again this was optional and a "level" above what most 7th and 8th graders take, as well as 8th graders who took the first part of alg1 in order to breeze through it freshmen year). There was also summer school if you wanted to get ahead although that option wasn't very popular. Most kids I knew also jumped around different levels taking Alg 2 and Calc1 before taking AP Calc2 or say they took AP Calc 1 but not AP Calc2. It was surprisingly close to college where you're just told to take classes in these categories and this is how many years of these classes you had to take and certain classes require other classes to already have been taken or to be taken at the same time. Science and Math crossed paths like that a lot.

Science was pretty much the same but you could further specialize ending in a physics or chemistry path or a more basic level of both if you wanted and basic levels of each were required before graduation.

English had less options but still ended up with 4 different levels you could end up taking your senior year, one of those being a "college" level course taught by a professor that drove in from a community college 3 days a week. We didn't have anything called "social studies" past elementary. We had geography, poly sci-ish classes (not called that but the name escapes me and the subject was basically the same), history etc. They each had 3-4 levels you could end up with your senior year as well and again you could sort of 'specialize' in your favorite.

This is ~5 years ago in a public school in Texas. The district currently has 6 or 7 highschools all about the same size with the same curriculum. I think its 7 now, they keep building more and I dont live in the area anymore and my parents rarely talk to me about it. Also just like to point out that you calling into question someone elses experience, given he did say "most", as atypical is kind of funny seeing as how you only really have on view point to look from as well and it is admittedly ~20 years old if not closer to 30.

Moral of the story is things change, and public education across the US varies WILDLY in terms of quality and choices available.

Also just remembered that for each of those AP classes there was a "Pre-AP" version. So make that 3 sublevels for each level.