Well, no - NeXTstep was already x86, as was Rhapsody - the work-in-progress name of the OS, all the way up to the release of the OS under name of OSX (OS 10), which happened when Apple were done porting everything to (legacy) PowerPC. After that, OSX was on PowerPC for just a short period (6 years?) before Apple went back to x86 again (no more need for legacy Os9 compatibility “layer” (BlueBox))
You can bet your butt that Apple made sure that OSX kept working on x86 as well through those years.