I don't believe I ever said heat was the cause, if I did I misphrased my point. Excess heat was absolutely the symptom, but it was a symptom of a design that was pushed beyond the limits of regular operation.
A two year old lithium battery under normal use will hardly degrade at all. Any design that pushed the limits so far that a degredation of a few percent over promised and under delivered. In Apples case it could be remedied with a software update, but that doesn't mean the device held up to the original performance claims over a standard life cycle of device use.
A two year old lithium battery under normal use will hardly degrade at all. Any design that pushed the limits so far that a degredation of a few percent over promised and under delivered. In Apples case it could be remedied with a software update, but that doesn't mean the device held up to the original performance claims over a standard life cycle of device use.