They've never quite come out and said it, but Fox seem to have regretted cancelling FIREFLY as the DVD sales of the series were quite impressive, even fairly early on, and combined with the ratings (a million people a week higher than DOLLHOUSE has managed) they probably could have kept it on a fair bit longer. They screwed around with it to a ridiculous degree as well, which they probably realise was a mistake in retrospect.

That said, it is true that Whedon has always had a much bigger name/acclaim footprint than actual viewers. The secret of keeping BUFFY and ANGEL going as long as they did was that they were relatively cheap to make.