Why is Barbara Gordon Still in a Wheelchair?

An incredible twenty-three years ago now, writer Alan Moore had Barbara Gordon, the former Batgirl, lose the use of her legs after being shot by The Joker in the landmark one-shot Batman: The Killing Joke.  This major game-changer for the Batman universe ultimately resulted in Barbara taking on the new identity of Oracle, becoming a major resource of intelligence and computer hacking for various DC Comics superheroes.

Appearing in such titles as Suicide Squad, Birds of Prey and various Batman books, Barbara has obviously grown as a character with considerable depth since her paralysis.  However, in a fictional universe populated with aliens, magicians and technological super-scientists, it seems increasingly awkward that she should be forced to remain that way.

It feels even more awkward when her fellow superheroes rarely address the subject of restoring Barbara's ability to walk, even if such a feat inexplicably continues to be beyond even their considerable powers.  I mean, these are people that risk their lives battling the nastiest, most impossible threats the entire DC Universe has to offer and you tell me that none of them can spare a single day or two to even attempt finding a paralysis cure for one of their own?  I'm turning the Peter Parker brand "With Great Power Comes Great Responsibility" Spotlight of Guilt on these heroes in particular...

• Batman -- Of all people, you would think Batman would do something about this.  Apart from failing to prevent the Joker from shooting Barbara, he's actually had his own back broken but was healed by special powers from his former physiotherapist, Shondra Kinsolving.  Even if Shondra wouldn't be able to heal Barbara herself, doesn't it seem highly unlikely that she's the only person in the DCU with such abilities? 
• Superman -- All those things he can do, all these powers, and he can't work in some time to travel out in space, another dimension or to the future to find a cure for paralysis?  Not just for Barbara, mind you, but for everyone else on DCU Earth?  What would Christopher Reeve do, Superman?
• Wonder Woman -- Two words:  Purple Ray.
• Steel -- Some time ago, Marvel's Iron Man was paralyzed from the waist down after being critically wounded by a bullet near his spine and built himself special "telepresence armor" that allowed him to walk.  Presuming John Henry Irons, DC's version of Iron Man, is even remotely in the ballpark as Tony Stark, you would think he'd at least build a prototype and let Barbara decide if she wanted to use it.
• Zatanna -- Two magic words:  Riaper enips.
• Nightwing -- Barbara's former boyfriend has had a number of run-ins with the megalomaniacal villain Ra's al Ghul over the years, so would it be too much to ask for him to track down one of Ra's restorative Lazarus Pits?
• Cyborg -- Almost the same reasoning as Steel, only Victor Stone has experience with cybernetic prosthetics replacing his mutilated limbs.  Think of what these two could accomplish together if they actually tried.
• Doctor Mid-Nite -- If anyone could pull this together, it's probably Dr. Pieter Cross.  As the main physician for the Justice Society and the Justice League, you have to imagine this is somewhere on his "To Do" list.