Apple would talk about the "MHz-myth" a lot. While it's true that MHz doesn't equal performance, Intel was doubling the PowerPC's performance most of the time. The G3 saw Apple do OK, but then Intel went back to dominating in short order. The PowerPC never matched Intel again.
It was really bad. People with Windows computers just had processors that were so much more powerful and so much cheaper.
You can say that Apple always charges a premium, but not too much today on their main lines. Apple simply doesn't sell low-end stuff. Yes, a MacBook Pro 2GHz costs $1,800 which is a lot. However, you can't compare it to laptops with crappy 250-nit, 1080p screens or laptops made of plastic, or laptops with 15W processors. A ThinkPad X1 Carbon starts at $1,553 and that's with a 1080p display rather than 1600p, 400-nits rather than 500-nits, 8GB of RAM rather than 16GB (both soldiered), and a 15-watt 1.6GHz processor rather than the 28-watt 2GHz part. Heck, for $1,299 you can get something very similar to the ThinkPad X1 Carbon from Apple (though with a 1.4GHz processor rather than 1.6GHz) - $250 cheaper!
The point of this isn't to say that you can't get good deals on Windows computers or that there's no Apple premium or even that there's any value in Apple's fit-and-finsh that you're paying for. This is to say that I remember things like the original iMac with CRT display, 233MHz G3 processor, 13" screen (when people wanted 15-17" screens), and an atrocious mouse going against Intel machines for half the price with nearly double the speed and better specs on everything other than aesthetics. Things were really bad trying to argue that someone should spend $1,300 for an iMac when they could get a Gateway, eMachine, Acer, etc. for $600 with a 400MHz processor rather than 233MHz. A year later, Apple's at 266MHz while Intel has released the Pentium III and is cranking it up from 400MHz to 600MHz that year.
Yea, you can point to $700 laptops today and say, "why buy an Apple for $1,300?" Sure, but at least I can say that the display is so much better (500 nits vs 250 nits and retina), it's lighter than those bargain laptops, fit-and-finish is so much better, etc. At least I'm not saying, "um, no...all those benchmarks showing the Windows machine twice as fast...um...and the mouse is so cool because it's translucent...you get used to it being terrible." It's very, very different from the dark days of 2000.
Plus, today, a price premium doesn't seem as bad. Back in 2000 when you thought you'd be upgrading ever 2-3 years, you'd be shelling out a lot more frequently. If performance doubled every 18 months, 3 years later you'd be stuck with a computer running at 1/4th the speed of something new. With the slowdown in processor upgrades, paying for premium hardware doesn't seem like throwing money away in the same way.
The article also paints the RISC architecture as superior. I'm not a chip expert, but most people seem to say that while RISC and CISC architectures have a different history, modern CPUs are hybrids of the approaches without huge advantages inherent in their ideology. Frankly, if Intel were able to get down to 7nm and 5nm, Apple might not be looking at ARM as strongly.
I think it also paints Apple as some sort of more demanding customer. In some ways, sure. Apple likes to move things forward. However, it's not like MacBooks are that different from PC notebooks. The difference is that Apple has options. They can move to another architecture. Windows manufacturers don't really have that. Sure, Windows on ARM has been a thing, but Microsoft isn't really committed to it. Plus, Windows devs aren't as compliant when it comes to moving architectures so a lot of programs would be running slowly under CPU emulation.
The big issue is that Intel has been stuck for so long. Yes, they've shipped some 10nm 15-watt parts and even made a bespoke 28-watt part for Apple. It's not enough. I'd argue that PC sales are slow because Intel hasn't compellingly upgraded their processors in a long time. It used to be that every 18 months, we'd see a processor that was a huge upgrade. Now it's 5 years to get that upgrade.
There's a trade-off between custom products and economies of scale. With the iPhone using so many processors and TSMC doing so well with its fab, Apple now kinda doesn't have to choose. Intel has been charging a huge premium for its processors because people were locked into the x86 and it takes a while for new competition to happen. Their fabs have fallen behind. It looked like they might be able to do 10nm and move forward from that, but that doesn't seem to be working out too well for them.
The transition from PowerPC to Intel was about IBM and Motorola not being able to deliver parts. They were falling behind on fabs, they weren't making the parts needed for Apple's product line, and it was leaving Apple in a position where they simply had inferior machines. The transition from Intel to ARM is about Intel not being able to deliver parts. It wasn't simply a short time when they couldn't deliver enhancements, but a decently long trend on both accounts. Apple knows it can deliver the parts it wants with its own processors at this point. The iPhone business is large enough to ensure that and they can make laptop parts that really fit what they're trying to market. Intel got Apple's business because they produced superior parts at a lower price. They're losing Apple's business for the same reason.