The consumption of a black hole depends on the conditions at the center of each galaxy. Unless something causes most of the galaxy to spiral inward, galactic black holes will run out of material around them in time.
We don't know why the universe expanded from it's initial conditions at the time of the big bang. Given the current state of the universe that we can observe, there isn't any known force that could have caused it, especially Lambda as it currently is. I expect that to know what happened, and what happens inside of a black hole would require a quantum theory of gravity or something similar.
As to what stops a black hole from doing the same, I'd have to say it's the fact that it isn't the Big Bang.