I believe you are correct. I suspect a big part of Apple's increased popularity since moving to x86 has been the ability to run an alternate OS either via dual-boot or in a VM at native speeds. While it was possible to run Windows in a VM back in the PowerPC days, it was sloooow. While switching to ARM would be relatively trivial for Apple's own software and even OS X applications, the downside would be losing easy/performant/power efficient access to non-OS X applications. That said, I expect Apple to make that trade-off sooner rather than later... x86 compatibility isn't nearly as important today as it was 10 or even 5 years ago.