Non-Intel processors in the Mac? Erm, yes.
The article states:
"Apple does have some experience using non-Intel processors in the Mac, albeit long ago."
Well yes, that's one way of looking at it. Another way of looking at it is this:
Apple's original PC line - the Apple 1, 2, and 3 - used 6502 CPUs.
The Macintosh started out in 1984 using Motorola 68000 CPUs, following that line of CPUs until the 68040. Then Apple moved the Macintosh line to the PowerPC line of CPUs starting in 1994, and most recently transitioned the latterly re-branded Mac line to Intel architecture CPUs around 2006.
In other words, Apple's PC line originated outside the Intel ecosystem, the Mac - being the Apple PC line which lasted - has spent most of its life not running on Intel CPUs, Apple has a good deal of experience of moving a PC line from one CPU architecture to another, plainly has no attachment to a particular CPU architecture, so why not a switch to a mixed IA/ARM Mac?
Whatever the plan actually is, I'd happily bet it'll work well.
Biting the hand that feeds IT
