Why do people care about screen readers? Is it because they are good people and want to make sure sight-impaired visitors are able to access their content? Or is it because they have contracts that require 508 compliance?
I guess it's a good question. At a recent conference it [website accessibility] was described as the digital equivalent to putting a ramp in at your door.
Where I work at the moment I'm required to comply with WCAG2 AA at a minimum.