We have to be careful not to throw the baby out with the bathwater here, though. Obviously accessibility is an important issue for both commercial and ethical reasons, but if you're talking about writing laws and severe penalties for breaking them then you will always have to choose what minimum standards you will always require and then accept that it might be unreasonable for a software developer to go further.
For example, suppose the entire purpose of a certain office application is to draw some clever visualisation that helps the office workers to understand complex relationships in their business data. Maybe that presentation style has been chosen based on years of experience and saves a lot of time and avoids a lot of mistakes compared to a simple text report or table of figures. However, maybe it also doesn't work for someone whose vision is too limited to usefully see or interact with the visualisation.
Perhaps you could present the same data and relationships in a different way, a format that would be more amenable to sound- or touch-based interfaces for those with severely limited or no vision. In reality, that might mean writing a second entirely separate application, one that might cost more than the original to implement and support, for an audience that will usually be very small and often empty.
So where should the line be drawn? In an ideal world we want to be as inclusive as possible regardless of anyone's individual limitations, but we also want to provide the most effective presentation possible to those who don't have the same limitations. In general doing both might be prohibitively expensive, so how do you make realistic, ethical decisions in this space, and given that every software application is different, how do you codify the standards you want to make mandatory for the accessibility reasons?