Various websites are reaching out to smartphone manufacturers to get insight on something they would probably never admit to doing anyway, based on all the flack Apple is getting. Thus far, HTC and Motorola have insisted that they do not slow down the CPUs in their devices when their batteries get old.
Apple claims this is not a bug, but a feature. Up until last week, Apple had not publicly acknowledged slowing down older iPhones, and it was not clear that the reason for slower iPhones was actually in the battery. All of this has spurred questions whether slowing down the processor of the phone based on its battery age is not a common practice among phone makers.