Resistance to using Audio and Video
Maybe by somehow making it easier and more effective than what they are doing now... and - in a way that doesn't take away from them being the center of attraction :) Let's face it, many lecturers probably get a kick out of 300 or so people coming to see them perform a lecture.. especially those that think or know they give good lectures. Recording their work threatens to take away from that. Its a bit like live musicians would have thought when the first record hit the market. Some would have resisted making recordings, and maintained their faith in the live performance.. education has always been slow to catch up with social changes, so perhaps the answer to your question lays in the history books of the music industry.
This is the only answer I can find, because clearly it is effective and helpful to students to have access to audio recordings. Since mini cassette technology - or portable audio recording, students have been recording lectures.. but its rare to find a faculty doing it for them..
Individual blogging and podcasting can be used in such a way to make a lecturer a super star.. in a lecturery kind of super star way (what ever that might be.. I shudder to wonder)..
BTW.. the link to your audio required me to sign in to listen.. that was an unnecessary barrier that stopped me listening to it..try using services that don't require such a think.. suggestion? Blip.tv