Are you saying OpenGL wasn't on Mac OS before Mac OS X? That's not true. Apple released OpenGL for Mac OS 9 in 1999.
WWDC 1999: Mac OS 9 - A work in progress https://youtu.be/LkmSrCsKPLk?t=1360
WWDC 1999: Mac OS 9 - A work in progress https://youtu.be/LkmSrCsKPLk?t=1360
Even on Mac OS it wasn't available, rather Quickdraw 3D was the API to go to.
Had Apple been successful with their in house OS, and surely they wouldn't have cared about OpenGL.