Commenter denis bider considers accessiblity an altruistic endeavor and suggests that it would be more efficient to outsource accessibility to another company.
Sure, why not. Just like in real life, you can hire someone to do your programming taxes for you. If you would rather hire another company to come in and add accessibility support to your application, then more power to you.
Yes, accessibility is one of those altruistic things, but so too is not consuming 100% of the CPU all the time, or being usable at high DPI or color schemes different from the Windows default. Sure, you can write your program so it doesn't work at high DPI, and requires the user to use the Windows default color scheme, and consumes 100% of the CPU all the time, but each time you do this, you alienate another percentage of your audience. (Not supporting accessibility will cost you a pretty large audience, because governmental agencies usually have accessibility as one of their requirements.)
And don't be so sure that the audience that appreciates accessibility is just your test team and people with disabilities. It also means that people can't write tools that extract the text from your program or use voice recognition to control your program.