The Dark Knight's Career Seems EXTREMELY Short. Thoughts?

https://www.reddit.com/r/movies/comments/6rajmf/rewatching_nolans_batman_trilogy_the_dark_knights/

A quick breakdown:
In Batman Begins, Bruce Wayne doesn't don the Batsuit until halfway through the film. It isn't specified exactly how much time elapses from that point until the end of the film, when Commissioner Gordon tells Bruce about the Joker. But even a liberal estimate makes it about a year.
When The Dark Knight begins, the Joker is running amok and the Batman is on his trail. "In the Gotham Tonight news segments released to promote The Dark Knight it reports on Election '08 and states that the attack on the Narrows -which happens at the end of Batman Begins- took place nine months previously." Source
Very little time passes during The Dark Knight, and at the end, Bruce and the Batman effectively go into exile. At this point, a conservative estimate would place the Batman roughly two years into his tenure.
Eight years later Bruce Wayne is living a reclusive life in Wayne manor and has not fought crime during that period. Again, Bruce does not put on the suit until a little less than halfway through the film. Then he gets broken by Bane and spends a couple of months in recovery. When he finally emerges from the pit/prison, he makes short work of Bane and Talia and the trilogy ends.
All said and done, Bruce is only the Batman for a little over two years, not including sick time. I understand that the Batman was a symbol; that Bruce deterred crime with the "shadow" of the bat, rather than fought it. But it just seems like a lot of pomp and to-do for such a short career.