With the iMacs and MacBooks this goes hand in glove. One of the problems right now is heat throttling as Apple designed for chips that Intel said would be ready...and then weren't. As a result Apple had to go with chips that had higher heat budgets then they designed for.
“Higher heat budgets than they designed for” is underselling it a bit, honestly. The i9 in the 16” is still rated for 45W TDP, but I’ve seen the CPU package of the 9980HK alone hit over 90W and hold it until forced to throttle. The 10980HK reportedly can hit 135W. Intel is using ever increasing power consumption to cover for the fact that they’ve been stuck on their 14nm process node for far too long. These 10980HK measurements honestly demonstrate that these chips are just as power hungry as their desktop counterparts under load, and getting noticeably worse with each generation. Intel’s 10th gen laptop chips now consume more power under load than AMD’s similar desktop chips (3700X with 8c/16t was measured at around 90W under AIDA stress test loads). It’s just that the 10980HK idle power is still quite good, while AMD’s idle power has generally been higher than even Intel’s desktop chips.
This trajectory is not sustainable for any laptop OEM long term. Apple just happens to have some experience building SoCs for performance in the low power regime, while other OEMs either play along with Intel or hope AMD can make a good enough laptop chip to let them switch.