I've seen quite a few ideas and bits of policy writing about accessiblity that could probably do with some updating. These are the 3 most common.
One of the problems with accessibility as a single concept is that it lumps together issues that are sometimes fairly unrelated.
Blind people have different accessibility requirements from partially sighted people, or those with motor impairment.
People with slow modems need different things from those on corporate networks with strict security. We need to think about separate requirements, ... separately.