I'm not trying to be funny. I'm dead ass serious. There are people who have worked through injuries that would make Edge cry.
Funk, Hogan, Taker, Flair....
Because of his injuries, Hogan has already become one of the biggest jokes in pro wrestling, but has never seriously worked through ANY of his serious injuries... and it's more about the want to work rather than actually working. Nobody said Edge didn't want to continue, the fact of the matter is that he can't, even if he wanted to. And I'm sure he'd rather live out the rest of his days at the best health possible, not risking paralysis night-in and night-out.
Ric Flair? Luckiest fucker ever. But Flair's spine wasn't deteriorating because of his injury, it healed very well.
Taker? A shoulder dislocation and a couple bad hips and knees. Surgery on those places ensures some extra time no matter when you get it done. Spinal fusion, in the neck, like Edge... forget about it.
And I'm not schooled up on Funk's injury history, but something tells me the guy hasn't had this deteriorating spinal issue. And I really don't think you grasp the fact that Edge's injury is DETERIORATING... meaning, his spine gets thinner and the nerves become pinched. Not only was he risking paralysis, but the possibility of death is great and real. If those nerves pinch a particular way, the guy could have a stroke. You're comparing standard (though in Flair's case a plane-crash isn't standard) injuries and healing processes to Edge's uncommon injury and NON-HEALING process.