That's a great explanation. If I recall, the move from 680X0 processors to PowerPC was because 680X0 were not keeping up with the speed and development of Intel chips and the move to RISC architecture would help Apple. It seems that story repeated and so Apple moved to Intel chips.
I think it was bigger than that. 68K was used by a lot of things that were not IBM PC-compatibles in the 1980s, e.g. Sun boxes, etc. The general view at the time was that CISC was a dead end and the future was RISC, and the *NIX workstation folks who likely sold the highest-priced 68K systems switched to their own RISC processors (SPARC, MIPS, PA-RISC, etc) first. That probably became somewhat of a self-fulfilling prophecy - with people abandoning 68K, Motorola slowed down/abandoned 68K development, etc. (Look at how few things used 68060s compared to 68020/68030/68040s)
Apple did not want a 'bespoke' RISC architecture (and worried that Motorola's 88K RISC architecture didn't really have any other major customers), so they thought that by partnering with IBM and Motorola on PowerPC, there would be a big ecosystem of non-Apple devices, e.g. IBM machines running various OSes, CHRP machines running Windows NT, etc, using PowerPC.
What no one anticipated at the time, I think, are five things:
1) Intel's massive scale/R&D/etc effectively let them engineer their way out of the presumed-dead-endedness of CISC/x86. So DOS/Windows/"PC compatible" land never had to transition away from x86 as many of the CISC naysayers expected.
I suspect that IBM/etc expected that x86 would hit a dead end, x86 buyers would be forced to look at something else, and PowerPC desktops from IBM would be a strong contender. Even if Windows remained popular, well, they had Windows NT for PPC...
2) Not only did x86 not hit a dead end, but in fact, due to economies of scale, Intel's manufacturing edge, etc, x86 started to pull ahead in performance. The RISC guys were beating x86 in the early-mid 90s; by the early 2000s, at least on the desktop/workstation side, x86 was faster and significantly cheaper.
3) The other expected applications for PowerPC basically went nowhere. Some PowerPC chips were used in IBM servers/workstations, but otherwise, PowerPC effectively became the bespoke architecture that Apple didn't want. The brave new world of a gazillion IBM boxes running OS/2 or Windows NT on PPC never happened.
4) Worse than that, non-server/non-embedded applications for PowerPC never materialized. This is what led to the disaster of the G5 - sure, IBM had a faster more modern PowerPC CPU that it could offer, but it had a server-grade power envelope. And no one wanted to make Apple a modern PowerPC processor for laptops, at least at a price point Apple was willing to pay.
5) The ever-increasing cost of building new fabs for smaller processes. It's not clear to me whether Motorola/Freescale, for example, had the volume to keep up with Intel/AMD-IBM-etc in the 2000s. And unlike in the 2020s where the foundries like TSMC/Samsung are at the cutting edge of semiconductor manufacturing, that wasn't the case in 2000-2005.
So... especially at a time when Apple had no in-house processor design expertise, Apple needed someone to
design and
fabricate a low-power processor on a cutting-edge manufacturing process, and to do so at a per-unit cost that made sense for iBooks. And that wasn't going to be either Freescale or IBM.
Meanwhile, Intel had come to their senses after the Pentium 4/HotBurst debacle and was re-optimizing their whole lineup around power efficiency, which is exactly what an increasingly-laptop-focused Apple needed. Didn't hurt that Intel also offered ready-made chipsets for memory controllers, I/O, storage, etc - things Apple largely had to design on their own for PPC.
And, I would add one additional thing - switching to Intel would let Apple differentiate itself with design and software and effectively take hardware out of the equation. No more 'oh, RAM type X is now half the price per megabit of RAM type Y, but our memory controller doesn't support RAM type X so we need to spend twice as much as the other guys for the same amount of RAM for another year while our team works on a new memory controller for type X RAM'-type dilemmas. A 2006/7-era MacBook was very, very similar internally to a Dell laptop... and that meant that they could ride the same trends on component types/pricing/etc. Even the 16:10 displays used at the time were not Apple-unique. Over time, of course, Apple ended up settling on the higher end of the Intel component ecosystem while Dell and co, at least on their consumer machines, focused on the low end...
(What's interesting, of course, is how Apple silicon now flips all of this upside down... largely by leveraging the smartphone economy's massive economies of scale, Apple is now back at something completely custom, but something custom that is basically guaranteed to stay ahead of the x86 Windows world.)