In order to make the 5.5" model of the iPhone 6 really thin, Apple needs to use a 2.5mm audio connector. But, since there's not a great deal of headphones out there that use a 2.5mm jack, it would be less attractive to upgraders and switchers to get a phone that will require them to use an adapter for their existing headphones or be stuck with the notoriously (or debatable) not-so-good signature white ear buds until headphone brands start releasing 2.5mm headphone models they could consider upgrading to. In order for there to be a good selection of quality 2.5mm headphones ready from launch day of the iPhone 6, Apple buys Beats. Bit ridiculous just to have a manufacture change their headphones from 3.5mm to 2.5mm it seems...? Well, I imagine this: Apple won't ship any headphones in the box, but instead give you a generous rebate for a selection of 2.5mm Beats headphone exclusives. Given how low the production costs of Beats headphones are said to be, iPhone 6 buyers could choose from free headphone models included with their phone purchase to 'premium' ones that bring very high profit margins for Apple. Apple would expect a significant number of buyers to choose the premium rebate/discounted headphones over the free ones. Having an established brand sell an exclusive range of headphones just for your device from launch, using that established headphone brand as a reason why people should buy an iPhone 6 (e.g. free Beats headphones for every purchaser), yet, managing to get every penny of the profits PLUS a streaming service as part of the deal which'll further help improve their own music streaming was too good an opportunity for Apple to pass on. So, due the thinness of the 5.5" iPhone 6 requiring a 2.5mm audio connector, Apple needs to not let that put off buyers by offering free select Beats headphones/rebates. The 4.7" model will have a 2.5mm connector as well but could've housed a 3.5mm one.