you don't have to know anything about the comic to get the story that nolan presented. the poster above already said it, but bruce was around for a while after batman disappeared. so the timelines were different which is why perhaps the people of gotham didn't put 2 + 2 together on the identities. the other point you seem to have missed is that during the time that bruce was around he invested the majority of the money in wayne enterprises into that fusion energy. the reason why that "gamble" didn't pay off and was seen as a bad investment was because they claimed it didn't work and hid the reactor since, as bruce and fox stated in the movie, it could be used to be turned into a bomb. it was only after this supposed flop of an investment that wayne seemed to turn into a recluse. at least, that's the way i understood it watching the movie. i pretty much thought the plot was pretty straight forward.

>My understanding was he went into seclusion following dent's
>death and that during that time, he messed up his investments
>by not being there mentally or physically to handle the
>issues. It was stated that they believed he was injured in
>some accident and that's partially why he hid, so to me people
>stopped seeing Bruce Wayne around the same time as Batman.
>
>To that I add, batman and Bruce Wayne both reemerge at the
>same time. I don't get how no one, except Blake and Bane,
>would make a connection.