We used to say this a lot in the Army when it came to being Infantry because you wouldn't guess how many times you did things outside your paygrade or MOS (Military Occupational Specialty AKA Job to you Civilians). It is a saying I have taken to martial arts as well, the fundamental principle of Mixed Martial Arts competition is in the idea of allowing all possible techniques to be available to a fighter. This has changed much of the make up of modern martial arts as ground work has now gained a great deal of popularity in martial arts. More importantly, the question of which is better, striking or grappling has remained unanswered as at different times strikers or grapplers have dominated in MMA competition. Thus proving that it is never the art or the techniques but the fighter which is of the most value.
As such, a person dealing with self-defense must extend their list of possible techniques to include "illegal strikes" for competition such as knife hand strikes to the neck or throat, eye gouges or groin strikes/grabs. Then you have to train to deal with multiple opponents, weapons defense, weapons usage (after if you can take a gun away from a mugger but don't know how to use it, your screwed). So how is someone to be able to effectively defend themselves?
Now I won't label all traditional martial arts as a problem, in fact the biggest problem in traditional martial arts has come from the realm of competition. The rules of Karate exclude the use of throws, joint-locks and chokes. So many schools which seek to draw in students (remember that dojo is a business) water down their training to focus on winning competitions, which draws in more students. Judo contains Atemi-Waza (striking techniques) which is not allowed in competition, and many judo schools often exclude these methods from their training and focus on competitive skill sets.
This isn't a bad thing, some systems are not competition arts, like Goju Ryu Katate or Hapkido which is a self-defense focused art and more combative in nature they focus on effect and so include a lot more Bunkai (Literally "Disassembly" or "Breakdown" meaning to take Self-Defense Applications called Oyo from Kata forms) then Kata. Goju Ryu being a Okinawan art is more focused on combat application and so many Bunkai techniques are taught to the students, performing kata so that they under the application behind the movement. This is a stark difference to Japanese Shotokan Karate, which save Bunkai for higher belts. Goju Ryu also focuses more on developing the body to withstand punishment and build up the body to deliver powerful strikes & destructive joint-manipulations.
Is Goju Ryu Karate better then Shotokan Karate, in my opinion yes... (and I offer this assessment as an example of the concept I trying to express here) but Goju Techniques & Shotokan techniques are the same techniques. What makes Goju Ryu better then Shotokan is the mindset on training & the goal of effective fighting skills. The techniques and forms are almost the same or very similar in nature. Can Shotokan attopt some of Goju's philosophy to make itself better? You bet... In doing so we come back to MMA were different martial arts are studied and to make up for gaps in the training of these arts.
My old Shotokan school was a bit of belt mill, the instructor did it to make extra cash and really didn't care a great deal for "tradition" in Karate. In fact, he encouraged cross training, so I also studied Judo and Sport Jujitsu. And yes, my Instructor awarded my a black belt as a child but, in his defense its business & those belts don't mean anything...
There is an issue with people over estimating the importance of an award. Things like skill come with hard work and not certificates, lineages & strips of colored cloth. Let me give you something to consider, which is more impressive? The guy with a "Ranger Tab" who earned in Ranger School, or the guy without a "Ranger Tab" but who parachuted into gun fire, chaos and hell on earth in a fire fight as part of a Ranger Battalion as a simple PFC without the advanced training of Ranger School? This is by no means to diminish the honor or the difficulty of earning the "Ranger Tab" this is to say their is a difference between training and doing it for real. No martial arts competition or school will ever put you in the same position as the real thing of fighting for your life.
Self-Defense is not limited by the rules of competition, just as Bunkai is not limited to the confines of Kata. The real thing is always going to throw kinks into your game plan. I have a friend of mine who is a superb grappler and he loves to point out he can submit about 8 out of 10 times. Thing is one day he was touting the superiority of his grappling skills and I by contrast asked him how he could grapple a 30-06 round fired from 200 yards away. His response was funny... "He looked at me and said a gun beats everything."
My reply was "No, it doesn't..." Few people can actually make that kind of shot or have a weapon that has been sighted in for that kind of shot. So its likely thy will either miss you or not kill with the first shot. So lets say the round misses you? What do you do? Unless you've been trained in a react to far ambush battle drill, you have no clue. You can look it up in the FM 7-9 if you like... Basically, you will do the same things kids in the Ghetto do when a drive by occurs, you drop down and crawl for cover or if no cover is available pretend to be shot.
In the real world, the world of the rising threat of terrorism you cannot be so restricted to thinking of self-defense in terms of martial arts techniques or competition fighting. Competition has it place in training and competition with the most techniques available for use is of course the best option. But, in the world of self-defense you have to be a Jack of Trades and Master of None. Learning things with the idea of adding tools to a metaphorical toolbox & not becoming a Master of a particular style or tradition. In this case, I have developed the Black Dragon Ninjitsu Course to develop skill sets at each rank, to move from striking range, to infighting range, to grappling range, to include tactics, strategy, stealth and survival training. To act as a guide to allow you to develop your own "Style" of fighting and act as a generalized platform for self-understand the growth.