Presumably partly because:
http://skypetips.internetvisitation.org/articles/record_skype_calls.html
...is not trivial and has drawbacks.
Who's running BHTV then? If they have any amount of resources they can make the process a "just push a button and, bam, you're on air, no special software besides Flash plugin needed". You know, like Ustream.
Latest Bloggingheads up with Robert Greene, bestselling author of The 48 Laws of Power and most recently The 50th Law ("Fear nothing").
Excellent commentary/summary by Andy McKenzie here.
The most important piece of advice I got from The 50th Law was "always attack before you are ready".