2) The average lifespan of an Apple device is 4.25 years
That should put to rest the "Apple's planned obsolescence" narrative, but I doubt it will. I think it has always been the case that Apple cares about building really good hardware that lasts. That's not to say that they don't make mistakes (they do), but they care most about making something good, regardless of the "business case."
On the most recent earnings call, several investors had questions about how Apple's new battery replacement program would affect business. For example, would the cost bring down profits, would the replacement prevent upgrades, etc. Tim's response was:
>On the battery, Toni, we did not consider it in any way, shape, or form what it would do to upgrade rates. We did it because we thought it was the right thing to do for our customers. And sitting here today, I don’t know what effect it will have. And again, it was not in our thought process of deciding to do what we’ve done. [1]
[0] - http://www.asymco.com/2018/02/27/the-number/ (this does not include iPods, I don't think) [1] - https://sixcolors.com/post/2018/02/this-is-tim-transcript-of...