My local anecdata: most people I know have 3rd party headphones if they actually listen to music. The people that use the in-the-box headphones from Apple tend to be the forever-on-a-call types. I struggle to see people buying these at this price point since there are plenty of bluetooth earbuds that are equal quality to Apple^, sub-$50, and won't instantly disappear in the couch. At Apple's price-point, you can already get a high-quality bluetooth earbud/mic from Audio-Technica. I would guess you'll have Beyerdynamic, AKG, Shure, and Senheiser all pop out a similar pair soon enough (Some may consider themselves 'above' bluetooth, though). I really don't understand their pricing. I could understand it if the equivalent Beats were $30 cheaper so they could create some tier pricing, however they are pretty much the same price.
^ Assuming they continue their trend of mediocre sound quality.
Thousand dollar phones with $100 month services. $159 earbuds. Think we are all in the matrix.