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.
That and they are not paying for Intel's profit margins either. Apple is the quintessential vertical integration - they own their entire stack.
Under load, my M1 laptop can pull similar wattage to my old Intel MacBook Pro while staying virtually silent. Meanwhile the old Intel MacBook Pro sounds like a jet engine.
I couldn't find good data on the older mbpros, but the m1 max mbpro used 1/3 the power vs an 11th gen Intel laptop to get almost identical scores in cinebench r23.
https://www.anandtech.com/show/17024/apple-m1-max-performanc...
Intel for the last 10 years has been saying “if your CPU isn't 100c then theres performance on the table”.
They also drastically underplayed TDP compared to, say, AMD, by taking the average TDP with frequency scaling taken into consideration.
I can easily see Intel marketing to Apple that their CPUs would be fine with 10w of cooling with Intel knowing that that they wont perform as well, and Apple thinking that there will be a generational improvement on thermal efficiency.
But that was my entire point (root thread comment.)
It's not that Apple was taking existing Intel CPUs and designing bad thermal solutions around them. It's that Apple was designing hardware first, three years in advance of production; showing that hardware design and its thermal envelope to Intel; and then asking Intel to align their own mobile CPU roadmap, to produce mobile chips for Apple that would work well within said thermal envelope.
And then Intel was coming back 2.5 years later, at hardware integration time, with... basically their desktop chips but with more sleep states. No efficiency cores, no lower base-clocks, no power-draw-lowering IP cores (e.g. acceleration of video-codecs), no anything that we today would expect "a good mobile CPU" to be based around. Not even in the Atom.
Apple already knew exactly what they wanted in a mobile CPU — they built them themselves, for their phones. They likely tried to tell Intel at various points exactly what features of their iPhone SoCs they wanted Intel to "borrow" into the mobile chips they were making. But Intel just couldn't do it — at least, not at the time. (It took Intel until 2022 to put out a CPU with E-cores.)
On a 15/16" Intel MBP, the CPU alone can draw up to 100w. No Apple Silicon except an M Ultra can draw that much power.
There is no chance your M1 laptop can draw even close to it. M1 maxes out at around 10w. M1 Max maxes out at around 40w.
Intel doesn't publish anything except TDP.
Being generous and saying TDP is actually the consumption; most Intel Mac's actually shipping with "configurable power down" specced chips ranging from 23W (like the i5 5257U) to 47W (like the i7 4870HQ); (NOTE: newer chips like the i9 9980HK actually have a lower TDP at 45w)
of course TDP isn't actually a measure of power consumption, but M2 Max has a TDP of 79W which is considerably more than the "high end" Intel CPU's; at least in terms of what Intel markets.
Keep in mind that Intel might ship a 23w chip but laptop makers can choose to boost it to whatever it wants. For example, a 23w Intel chip is often boosted to 35w+ because laptop makers want to win benchmarks. In addition, Intel's TDP is quite useless because they added PL1 and PL2 boosts.
The major pains for Apple was when the thermal situation was so bad that CPUs were performing below base clock. -- at that point i7's were outperforming i9's because they were underclocking themselves due to thermal exhaustion; which feels too weird to be true.
My 2019 macbook pro 15 with the i9-9880H can maintain the stock 2.3GHz clock on all cores indefinitely, even with the iGPU active.
And you can compare both of those and Intels newer chips to Apples ARM offerings.