Apple’s sales haven’t really been affected. From personal experience I don’t miss it on my iPhone. I’ve used the adapter maybe a dozen times in the year I have had the phone.
I mean, at home I've got Chromecast Audio or Bluetooth speakers. At work or my desk at home I don't listen from my phone. And on the go I really hate cables, I always fear that I'm going to damage the port when walking with the phone in a pocket and positioning the cable is awkward with a warm jacket in winter.
Is my use case really so atypical?
If you really care about sound quality you weren't using the headphone jack on a phone (and its not so great DAC) anyway.
Complaining about the sound quality of earbuds is only "silly" if the iphone DAC is so bad that one wouldn't tell the difference between a good and bad earphone, which is clearly not the case.