That doesn’t make sense: everyone else got hit by Intel’s failure to deliver, too. Even if you assume Apple had some 4-D chess plan where making their own products worse was needed to justify a huge gamble, it’s not like Dell or HP were in on it. Slapping a monster heat sink and fan on can help with performance but then you’re paying with weight, battery life, and purchase price.

I think a more parsimonious explanation is the accepted one: Intel was floundering for ages, Apple’s phone CPUs were booming, and a company which had suffered a lot due to supplier issues in the PowerPC era decided that they couldn’t afford to let another company have that much control over their product line. It wasn’t just things like the CPUs failing further behind but also the various chipset restrictions and inability to customize things. Apple puts a ton of hardware in to support things like security or various popular tasks (image & video processing, ML, etc.) and now that’s an internal conversation, and the net result is cheaper, cooler, and a unique selling point for them.