For the companies, it's usually a case of weighing how much adding the feature will cost vs. how much they'll expand their market by adding it. For Fairphone, their whole schtick is that their phones are repairable and upgradeable, so in this case it's that they've determined that there's enough demand in the U.S. market to justify the cost of entry, as they've already added the features. In this case, the majority of people will probably not purchase a Fairphone, but that's not their goal, they occupy a market niche.