The dilemma the BBC has is that if they don't make populist shows that attract ratings, then they won't attract the 'talent' who want the ratings and exposure, nor will they get to work with the writers, production companies etc who seek ratings for obvious reasons (they have to write CVs too, remember).
Sometimes recruiting presenters, producers etc. to make one populist entertainment show will mean that the BBC has those people on board and signed-up to make other TV shows (this can save time and money as a lot of staff will be shared between different programmes/projects - e.g. I know someone who as worked on Match of the Day...and Miranda). If they don't get the best talent, producers, etc. working for them, then people will complain that the BBC never produces anything decent!
In short, the BBC has to make the populist, lowest-common denominator stuff in order to fund and staff the production of the quality stuff in the most efficient and cost effective way. It is also obliged to make those crappy programmes that appeal to a particular demographic under it's public service remit (alas, a lot of people like programmes such as The Voice, even if we don't). Unfortunately that means quality programmes get altered or dropped altogether, but I think the balance is still worth the license fee. For every 'Stacey Dooley Investigates', we get a Louise Theroux documentary.
