Cash-Cow Franchise: There's a good reason the Batman mythos is a victim of Adaptation Overdosed. Give or take Spider-Man, Batman is the highest-grossing solo superhero franchise of all time all media and merch combined. No wonder Warner Bros. regularly wants to reboot him moviewise.
Adored by the Network: Yes, Batman has so many ongoing comics published (with two being the bare minimum) mostly because comics starring him sell, but also because many comic writers have a Batman story they want to tell.
Everybody Smokes: Despite the fact that Golden Age Bruce Wayne is well known to smoke a pipe (and the occasional cigarette), he actually only smokes for a relatively short period of time, from his debut in Detective Comics #27 to the final regular appearance of the pipe in Detective Comics #51, two years later. The pipe makes an occasional appearance in a panel or two in Detective Comics #74 and in Batman #36, but Bruce never smokes regularly after those first two years of publication.
Recycled Script: One of Hugo Strange's earliest stories had him unleashing a fear-inducing powder on Gotham City; the Scarecrow debuted less than a year later (though he didn't use his fear gas then).
Science Marches On: The character's been around for over 70 years, so this is a given. For example, Batman started out in the 30's as a rich guy in actual tights with a Bulletproof Vest, a silk rope, smoke bombs, and a souped up but otherwise normal car. Nowadays he wears a full suit of kevlar armor loaded with high tech gear, military level weaponry, and the Batmobile along with nearly every kind of vehicle he could need. Although as things like carbon nanotubes become more common in the future, it'll be interesting to see how the writers can maintain the dramatic tension when the batsuit seems damn near indestructible. The writers of Batman Beyond successfully maintained dramatic tension when Terry was going around in flying power armor. When technology reaches the point where the Bat-suit has carbon buckytube armor, that only means the Joker will be shooting at it with a rail gun.
On the flipside, Batman's aerial vehicles are rarely seen these days over Gotham, as the risen level of civilian air traffic and -surveillance would make that a safety and secrecy hazard much more than in the old days.
This image◊ was created in case Jason Todd was voted to survive A Death in the Family. A very similar colored version (here◊) was printed in Batman Annual 25, which recounts Jason Todd's resurrection, as well as the reality-warping that caused it.
Dick was going to be Killed Off for Real in Infinite Crisis. For the same reason that saved him in fact. Considering how much emotional weight came from Barry Allen's death he could have been gone a while...
In the early 00's, there was brief talk at Warner Brothers of possibly making a live-action Batman Beyond movie to reboot the Batman franchise but the idea was passed over for Batman Begins instead.
Hawkfire almost got featured, alongside Beast Boy and a host of other 1970s characters, in a spin-off called Titans L.A. As Bat-Girl, she was initially set to be part of the main '70s Teen Titans team and be involved in a love triangle with Robin and Duela Dent, but DC pulled the plug on the title before Bob Rozakis could get to those plans.
◊ was created in case Jason Todd was voted to survive A Death in the Family. A very similar colored version (here
