Re: 8 years of no Batman or Bruce Wayne, and NO ONE could pick up the trend?
I think there's enough wiggle room there to say that the last time Bruce suited up as Batman before Bane was not the night of Dent's death. The process of the Dent Act being implemented and Blackgate being built would not have happened overnight and I could easily see Bruce going out there in a highly clandestine fashion in that interim. Blake's line about "Harvey Dent Day" being the last confirmed appearance of Batman eight years prior can support this. I also just really love the idea of Bruce watching Batman become obsolete with the heightening of the police's crackdown on crime while at the same time focusing more and more on philanthropy as 'Bruce Wayne'. It's a reinvention of both of his duel personas and the temporary failure of them.
O Captain! My Captain! Rise up and hear the bells.
Rise up, for you the flag is flung, for you the bugle trills.
For you bouquets and ribbon'd wreaths, for you the shores a-crowding.
For you they call, the swaying mass, their eager faces turning.