Why don’t more university have rigorous introductory math courses for math majors?

<p>I’m a high school senior and right now I want to be a math major (and I know this will probably change because I don’t, y’know, know any math).
My high school doesn’t even have AP Calculus AB, and I’ve had to go out of my way just to take linear algebra, differential equations, etc. (which aren’t proof-based as far as I can tell) in high school. Even doing this is pretty rare unless you go to a really fancy high school, which most people don’t.
I won’t be going to a top school (my ECs suck and I have no money), but the level of math I’ve reached is decidedly not the bad part of my resume.</p>