Philosophical question - why do people with disabilities have the right to higher priority than everyone else? Let's say you've calculated that there are 4000 blind people who might be interested in your website, but 11000 Spanish speakers, 9000 Korean speakers and 7000 Portuguese speakers. If someone comes to complain about accessibility for the blind, won't it be perfectly reasonable to answer (in more polite terms) "no, we won't handle you, we're going to do a Spanish translation first, then implement UTF-8 so we can do a Korean translation, then do the Portuguese translation, and only then maybe get to you"?
The Spanish speakers might be only a niche in the case of this one website, but they don't face being a niche practically everywhere they turn. I'm not going to weigh in on how that difference should affect how you deal with accessibility, but it's a real one.
