Not every school has AP classes. In fact there's a direct correlation with AP classes existing in schools in neighborhoods where income is higher.
This is why MIT got rid of considering Subject II tests because even on top of already relatively wealthy select schools that offer AP classes only a select few of those offer classes that prep you for subject II test.
It's essentially exponentiating the amount of opportunities rich kids have to slice themselves within percents different from other rich kids at their school but overall entirely leaves behind students who weren't lucky enough to born in a neighborhood with a tax bracket that determines the schools funding.
This is why MIT got rid of considering Subject II tests because even on top of already relatively wealthy select schools that offer AP classes only a select few of those offer classes that prep you for subject II test.
It's essentially exponentiating the amount of opportunities rich kids have to slice themselves within percents different from other rich kids at their school but overall entirely leaves behind students who weren't lucky enough to born in a neighborhood with a tax bracket that determines the schools funding.