If it's time to make another CPU change, why not switch it to one that you control completely? Motorola->PPC->Intel->Apple. It just makes sense that's where they'd ultimately want to go.
So you don't have to kill all of the software currently running on your customers' machines.
I bought a PPC Mac 9 months after they first made the switch. Most of my software was already native. Within the next year, all of the important software was native.
With recent changes to the OS, a decade of instability with every update every year, the recent hard deprecation of 32 bit binaries, and now moving to an unproven ISA for those particular workloads - all while Windows and Linux have closed the gap, mostly... the situation is a bit different.