Probably going to take a while before the 28-core Intel Xeon W Mac Pro is replaced with an ARM variant.
The ARM-based laptop will be the iBook (following iPad, iPhone patterns).
My best guess ...
On the portable side though its a no-brainer. I don't see Apple having x86 in new laptops at all after the transition.
But Apple may stop making high end desktop systems all together so it is possible. It's a very small part of their revenue.
That's what they said when the Mac Pro was neglected and they still designed a brand new machine to sell.
In the time since Hackintoshing first started in 2006-ish to now, Linux has become a real desktop competitor.
I think most people who bother with the headache of Hackintosh are better off on Linux anyway.