In the 40’s Batman was a dark avenger then in the 50’s he became a more pulp, campy hero.
In the 60’s Batman was redefined by the Adam West TV show and made Bruce Wayne into a fun loving good samaritan with a level of camp that rivaled that of the Christopher Reeve Superman.
Then came the 70’s and 80’s that brought Batman back to his roots of a dark and brutal crusader in a never ending war against crime, with books like the Killing Joke and The Dark Knight Returns.
Then in the 90’s there was a focus on making Batman more extreme, making him stand among the gods of the Justice League.
And now the modern era, after 78 years Batman is one of the most profitable and well known characters in the world. And probably won’t be going away anytime soon…hopefully.