I don't know if it is sensible, but here's my answer: there is! When BBC4 broadcast the sessions of Martin Cathy and others from the Union Chapel, they got more emails and messages than they (BBC4) had for any other music program. That will have helped persuade the BBC to broadcast more, such as the Folk Britannia series. And strong feedback to that - providing its not too negative - will make putting more on easier in its turn.

As to getting off BBC4 onto more mainstream channels - I'm not sure it will happen because folk is still a minority interest however you cut it. But with growing availability of the free digital channels, I'm not sure that's so important any more anyway.