The problem with the BBC is the same as with all massive organisations - government, NHS, BBC - the list goes on - it's accountability - or rather lack of it.
The entire culture revolves around the fact that none of these people have to account for the money they spend. It's like Monopoly, except they get paid a lot for it. The money isn't real to them, there are no real consequences, nothing really happens to stop this kind of thing, so it carries on.
Accountability. Any party that ran with that for a campaign, and guaranteed to make it work would get my vote, and I suspect, a few million others.