Innovators Dilemma.
I think you need to look at this from another angle. Yes, Apple did make some excellent choices, but the market was Intel's to lose.
The difference in the chips isn't limited to the 5nm, memory pooling, etc etc. Look at the base x86 vs ARM core architecture, and that is where you'll see the problem Intel had.
I'm sure there were discussions inside Intel which went along the lines of one person arguing that they had to start developing ARM based or other RISC based chips, and somebody else countering "but at Intel we build for the desktop, and servers, and RISC processors are toys, they're for mobile devices and tablets. They'll never catch-up with our..."
This change in architecture was a long time coming. As we all know, there is very little we do with our computers today, that we can't also accomplish on a phone (or tablet). The processing requirements for the average person are not that large, and ARM chips, made by Apple, Qualcomm, Samsung, or anybody else, have improved to the point they are up to some of the more demanding tasks. Even able to play high quality games at a good frame-rate or edit video.
So, now we have to ask, what was delaying the move from x86 to ARM. Apple aren't the only ones making ARM based computers. Microsoft has two generations of ARM based Surface laptops out, and I think samsung has made one too. I'm sure there are others. This is a wave that has been building for a long time.
So, now we can look at why Apple was able to be so successful in their ARM launch compared to Microsoft and the lackluster reviews of Windows based ARM devices.
From my understanding, it isn't the 5nm technology, though I a no expert in chip design. However, as you state, Apple was able to pool memory, and put their memory right on the chip, which (from what I understand) saves overhead of transferring memory in and out, as well as allowing CPU and GPU to share memory more efficiently.
As I understand it, the Qualcomm or other chips have a much smaller internal memory footprint, expecting the memory to be external to the CPU/GPU. Perhaps because this is just always the way it has been done.
Now this is where Apple's real breakthrough comes in. First off, they have the iOS app store and all the apps now available to use on desktop. This means all the video editing or gaming apps that were already designed for iOS can now run perfectly fine on the "new" ARM architecture.
Then there is Rosetta2. Apple understood how important running legacy software for a small number of their users would be, and I suspect they also had very good metrics on what those legacy programs were. They did an exceptional job on Rosetta (from what I understand), and should be commended on that. Though most users will likely never use Rosetta extensively, it goes a huge way to making the M1 chip an absolute no brainer.
Compare Rosetta to Microsoft's attempt at backward compatibility, and the difference seems glaring. HOWEVER, I think again this comes down to strategy and execution. Apple knows that only a small number of their customers need a small number of apps to run in Rosetta. Microsoft, having both a larger user base, AND much more bespoke software running on their platform, don't have this luxury.
I'm sure there are other factors, but my thinking is it is less about direct technology and more flawed strategy/execution from Intel and absolutely amazing execution from Apple.
I'm very torn by this all tbh. I've been an Apple hater for a long time. Every Apple product I've bought has turned out to be crap (except my original generation 2 iPod, it was truly magical). I'm beginning to think Apple may have actually got the upper hand here.