To further complicate matters, Apple is releasing/has released an iOS update to deal with overheating issues on the iPhone 15:
Apple said that the new iPhones were running hot because of a combination of bugs in iOS 17, bugs in apps, and a temporary set-up period.
www.cnbc.com
Reading between the lines, it looks like A16 is too much for the iPhone's cooling capabilities. Apple likely let it run extra hot to hit performance targets (or get as close as they could). Now that they've flooded the market with benchmarks of the release firmware, they can throttle it back and pretend nothing's wrong.
It shouldn't surprise anyone if A16 hit lower GB6.2 scores after the update.
It's just loop cycling some routine by accident until the whole thing overheats, looks like some interaction that worked fine on all previous ios versions but the new version changes the behavior blah blah blah classic software overheat bug.
Pretty much all phone manufacturers run their phone at 5w initially until heat buildup requires them to lower it to about 3.5w. It's not even cheating so much as the expectation that initial tasks will be highly bursty, so executing them as fast as possible is a priority and running into heat issues isn't expected because the activity won't last long. But a lot of benchmarks can run at max speed for a long time, thus throttling sets in there even if it wouldn't for burst activity.
It gets worse as well. We can look back to the Samsung/AMD 920 vs Snapdragon, uhm, stupidity, to see why manufacturers shouldn't throttle immediately. The Exynos with the custom AMD/Samsung GPU in it was in a phone that was set to throttle for long term stability. The Qualcomm chip was in otherwise the same phone, and was not set to throttle. Headlines screamed that the Qualcomm one was faster and the custom GPU "an utter failure", a narrative that survives to this day, despite different testing conditions. When set to the same conditions it turned out the custom AMD GPU was slightly better in terms of performance per watt than the Qualcomm one.
So not only is throttling not cheating, at least when it comes to quick bursts, it also needs to be off by default because the internet will be filled with screaming headlines about how much of a useless failure the phone/chip/etc. is if throttling is on, even throttling is a better benchmark for gaming (which is obviously expected to last long enough to throttle). Phone manufacturers don't really have a choice here.