The injuries are similar in boxing as football, i.e. CTE, only severity is different. Boxing used to be popular during the post WWII era but eventually faded as more and more boxers died from head injuries. Today, boxing is pretty much dead aside from a few big names.
It's a real stretch to pin the problems in boxing on CTE or the health plights of former boxers. Boxing croaked primarily due to lack of exposure. It went from free TV to basic cable to pretty much invisible except PPV events. Toss in too many weight classes, belts changing hands in court rather than the ring, an alphabet soup of competing federations with unique paper champs, the stench of big promoters limiting matchups and fixing fights, "big" fights that don't live up to the hype and a complete inability for the average fan to follow the sport and it's a recipe for disaster. Boxing was on its death bed long before CTE/concussions and past champs with brain damage became an issue.
Boxing used to have THREE champions of the world, lightweight, middleweight and heavyweight and even casual fans knew who they were. How many boxers today are "world champions"? 50, maybe 60? Can anyone except a real expert name more than 2 or 3 and which belts they hold? Hell, a couple of years ago one of the lightweight divisions four different champions and every single one of them was named Diaz. That's not a joke, four different men with the last name Diaz were "Champion of the World!" in the same weight class. And nobody knew who any of them were. THAT is what killed boxing.
At this time there are THIRTEEN world champs in Heavyweight, Junior Heavyweight and Light heavyweight classes alone. THIRTEEN. Name one except one of the Klitschko brothers.
Ooops, I have to correct myself, it's not 50 or 60 world champions, it's 82.
http://en.wikipedia.org/wiki/List_of_current_world_boxing_champions