Does it matter in this case? If the remaining headphone users stick with whatever headphones come packaged with their phone for free, then they still wouldn't be using the audio jack with the iPhone 7, as the iPhone 7 comes packaged with lightning headphones.
How many headphones are people even buying? I have a drawer full of headphones I have collected over the years. Not at all surprising people would only be buying wireless headphones, but it does not mean they are more commonly used.
Depends on what you mean. I have two pairs of headphones at any given time. One is a high quality over ear set for work/transit/home. The second is a "beater" cheap pair I bought at CVS that I wear when working out or walking. I lose the beater pair all the time, but don't care because they are cheap.
