and it kind of hinted that "Robin" would pick up the mantel when he discovered the Bat Cave at the end of the movie (hopefully that isn't a spoiler for you). The Batman franchise could continue with that idea where Bruce Wayne gets too old to continue being Batman so he finds a "Robin" that he can train to eventually become his replacement. Batman Beyond is the cartoon series I'm thinking of where a 60 or 70 year old Bruce Wayne is training Terry McGinnis, who is still in HS, on what it takes to become the "Batman." In that series there really is no Robin other than the former Robins that make appearances throughout the series.

I never owned any of the comics, but I think the comics may have explored that angle. I big into the Batman cartoons/cartoon movies and I know those explored that angle. For example, as Dick Grayson continues to grow up, he goes from being Robin to out on his own as Nightwing. After Dick, I believe Bruce has 2-3 (maybe 4) other boys to assume the Robin identity. I think Jason Todd is the next to replace Dick and when he grows up he eventually becomes the Red Hood. Tim Drake and Damian Wayne (Bruce's and Talia al Ghul's son) are the other 2 that come to mind.

I don't believe any of the Batman franchises have truly explored either angle. Now the Tim Burton franchise did tease about the possibility of Robin becoming Nightwing in the movie where Uma was Poison Ivy and Arnold was Mr. Freeze.