We can blame Apple for using chips that are too intense for their laptops, and we can blame Intel for making garbage chips that can't really perform in real world cases while spending a decade not bothering to innovate. Apple at least is moving away from Intel as a result of all of this, and I'm really impressed with how well the M1 transition has been going.
Not to say that M1 isn't amazing, but I think Apple has been preparing for this for a while and needed to make sure it would succeed even if their ARM CPUs weren't quite as groundbreaking as they turned out to be.
Or longer, really; while everyone, of course, loves the 2015 MBP, they're mostly thinking of the integrated GPU one; the discrete GPU version was pretty thermally challenged. Arguably Apple's real problem with the post-2015 ones was that Intel stopped chips with fast integrated GPUs, so Apple put discrete GPUs in all SKUs.
Possibility 2: Apple had a master plan to intentionally torpedo performance in order to make their future first-party chips appear more competitive
It's absolutely possible to do high end Intel in a compact laptop with relatively good thermals - look at thin Windows gaming laptops for plenty of examples of this (and these have way beefier GPUs than macbooks too).
The power draw drains batteries, and the heat is... very annoying at best. I have used a couple ThinkPads and a Dell XPS over the past 5 years too, and all of them had the same issues where they'd constantly be pushing out very hot air, and the battery life was never more than 4-6 hours.
I went to ifixit and clicked the very first laptop teardown I saw, it has one. https://guide-images.cdn.ifixit.com/igi/gnBU5dVYrIhInIXV.med...
Or, let's see, razer blade stealth, that's a 3 pound laptop. https://guide-images.cdn.ifixit.com/igi/nHPaankElOWQndsv.ful...
What's a light 15 inch laptop, XPS 15 7590? https://i0.wp.com/laptopmedia.com/wp-content/uploads/2020/01...
Acer swift 5 SF515, "lightest 15 inch laptop on the market" https://i1.wp.com/laptopmedia.com/wp-content/uploads/2019/01...
LG Gram https://guide-images.cdn.ifixit.com/igi/fFlFJB3PKThJs3TA.hug...
They've gotten around it with M1 by building an entirely new chip that's power efficient enough that it practically doesn't need good thermal design to perform near it's peak. It's an impressive technical accomplishment, but it's also hilarious that Apple had to go this far to cool a chip properly.
That's just not a defensible position to take.
Intel's inability to execute a node transition has led to a situation where for years their only way to increase performance has come at the cost of major increases to power and heat.
>Whilst in the past 5 years Intel has managed to increase their best single-thread performance by about 28%, Apple has managed to improve their designs by 198%, or 2.98x (let’s call it 3x) the performance of the Apple A9 of late 2015.
https://www.anandtech.com/show/16226/apple-silicon-m1-a14-de...
https://discussions.apple.com/thread/250943808
It's clear they have hit a limit of what they could really do with Intel's top of the line processors from a thermal perspective, with the form factor they want to deliver.
Now I have sort of an expensive paper-weight sitting next to my M1.
That was a bug on Apple’s part, not a feature. Case in point my Kaby Lake Windows laptop package power draw is less than 2W when plugged into 1440p.