The original films had space age technology, in both the 1968 version and the 2001 reboot, but in the prequels the world ended in like 2010-ish. So basically, they’re not prequels. Also, the 2001 version sort of implies maybe the Apes aboard the Oberon may have started the Ape Uprising.
EDIT: And the original trilogy actually shows the ape uprising caused by timetravelling apes after the 2nd move uh… made continued living on the planet somewhat problematic for the apes.