You seem pretty certain about their intent. The truth is Apple added battery throttling in iPhone 6 and up not in their older phones even though their older devices were capable of CPU throttling as well. For example, the iPhone 5S would throttle if it got hot enough to protect itself, yet it didn't receive the same throttling feature for the battery.

https://arstechnica.com/gadgets/2013/10/ipad-airs-a7-chip-is...