The core of MacOS (NeXTStep) was already ported to x86 long before Apple was even involved. Remember NeXTStep ran on x86 in the early 90's, as they exited the hardware business. It was not compelling for server workloads. It was also very picky on drivers, as the other poster implies. Plus it was difficult to build open source software for (SunOS was the gold standard for commercial Unix at the time. Everything you downloaded ran on Sun!)
I knew guys who ran early ISPs, tried it for servers, then realized they'd be better off with a Sun box and then eventually early Linux (Slackware). They were trying to run a news server off of it, IIRC.
However, the point remains that Apple ran consumer products on Intel chips for 14 years or so and this was successful. I'm trying to parse out the claim being made. Eg. Is it an argument that the timing would have been bad in the 1990s? Notable that Apple also killed the experiment around PowerPC clones around the time Jobs came back.
Timing does seem bad, seeing they had transitioned to PowerPC only 4 or 5 years before NeXT was acquired. And Intel had not yet really taken a huge performance lead. PowerPC's were still pretty competitive. It wasn't until the mid-2000's that it was clear they were not going to get a G5 or whatever running in a laptop.
Apple also wasn't rolling in cash like the are today. They were struggling. They wouldn't have had the resources in the late 90's to support consumer-level x86 and the various hardware/driver configurations. NeXT was fine with supporting a limited set of configurations since they weren't targeting the "consumer" anyway. They were targeting high end commercial "workstation" customers. NeXTStep 486 cost something like $800 if I remember. The developer tools were more $$$. The people running that stuff could afford to spec out their machines properly.
Or perhaps you mean porting Classic Mac in the 90s would have been a bad idea?