I personally think there isn't enough publicity out there aimed at developers; so that they realise the issues, and then care enough to act on them. But who has the responsibility for this?

Developer's have really jumped on the 'standards' bandwagon and cut down their peers not joining them. It's a great situation; one that needs to be replicated in this area. However, to some extent, I think it's beginning to be that way with some of the developer's truly caring accessibility: not enough, though.

I think that large companies are beginning to worry about the accessibility of their websites due to the laws being passed in many Western countries. But, I agree, that there aren't enough high profile cases. During the Australian Olympics, the Olympics Commitee were sued by a blind man, who couldn't navigate their site. That made a few companies sit up and listen
http://news.bbc.co.uk/1/hi/world/europe/1868566.stm

I always try to make the site's I make as accessible as possible - but apart from that; I don't see what else an individual developer can do. I think at the moment, the ball is in the court of the governments, disability related organizations, and the disabled community, to highlight their cause and make the big companies breaking the rules pay for it.