Well, the counter argument @purpletitan would suggest only students with the top course available to them would do well, and that has not been show to be true, as far as I know.
I think there is also an overweighting of value of HS AP courses, many of which are more about aggressive time management (and “firehosing” information) than a genuine learning experience. (And this is from someone who has watched a number of kids go through various programs.)
I’ve also seen kids who took APs then jumpt to the next level class in college, and I’ve seen some re-do their APs while I’ve watched others who did not do APs then do the college level equivilent. I don’t know that there is any pattern as to how well the HS AP course prepared them for various college level courses. One of my kid’s current HS Civ class even uses the AP book, but is not an AP or Honors, and is one of the most demanding, best college prep courses in the school, simply due to a crazy good teacher. But this is merely anecdote.
I don’t have any studies, but I bet that for most smart, top of class students, whether they got exposed to an AP and pulled the A or simply took the top track “regular” or “honors” at their school, the college outcome is not that different.
For most students I’ve observed, both teaching college level courses and watching kids go through college, knowing how to learn and have a work ethic tend to be way more important than specific knowledge brought to the course.