You don't need any non-standard input elements to make web site accessible. In fact the opposite is true: if you only use standard HTML elements, chances are your web-site is going to be fully accessible. It is when developers decide to use some fancy javascript instead of a standard button, or some other fancy form controls, with tons of javascript, this is when screenreaders tend to have problems trying to figure out what's going on.

For small businesses I imagine the biggest problem is that they only have only one engineer to support a web site, and he is not familiar with accessibility standards (justifyably so, because there are so few blind people out there), and he'd have to learn these standards and test the web site for accessibility problems - all these actions require time.