Google,Yahoo, Bing, Search Engines
Having a web site that cannot be read by a blind person means that like the very disabled people who cannot access your content, Google , Bing, Yahoo, Altavista,Hotbot, Yandex cannot either.
No search engine to share your content and that is the nub of it. No search engine = no income.
Having a web site without making it accessible to all is like having a piece of blank paper and saying to everybody look at my great brochure!! Look Look and no one sees a thing. Except you.