I find your argument mute. As most computers are not design for the blind or sight impair. Sure they can be modified for use with the blind.
I don't understand your comments. Modern computers have many "accessibility" features built-in. HTML has "accessibility" features built-in. Granted a blind user will probably want to buy a 3rd party screen reader app to best make use of the accessibility features built into computers -- but then again the sighted iPad user will have to download a separate Apple app just to be able to read books! Windows 7 comes with a basic screen reader. For an overview of these issues see for example: http://www.microsoft.com/enable/ Blind users have been using text-to-speech with computers since DECtalk 1984. A notable user you have probably seen and heard on TV is Stephen Hawkings.