I have to disagree no matter how ideologically incorrect it may be. No art is good at everything. Every art is lousy at something. Boxing has no wrestling. BJJ has nothing but the most rudimentary striking. TKD weapons do not exist. Sera has no ground grappling. Kendo completely sucks at empty hand fighting. The facile "They're all good, and if you just explore your Art enough you'll find what you're looking for" is a nice sentiment on the surface. What it does is blame the student for the inevitable deficiencies of any particular style.
First I should have said I disagree with you kinda because I think we have 2 conversations going on here in this post now - Specialized MA and non-specialized MA
Certain styles were designed for a very specific reason such as kendo. If, in real application of kendo, you are wielding a katana then a grappler is best not to attack you lest he get cleaved in two. However if back in the old days of feudal Japan the sword was lost they did have other Martial arts to fall back on to fight with such as Jujitsu.
In many traditional CMA styles there is weapons training but that part of the training when it comes down to a typical self-defense situation is for the mist part useless. The fact is you are not likely to be carrying a Dao or a Jain with you wherever you may go just in case you need to defend yourself. Same goes for guns, chances are there are very few martial arts that train you how to shoot.
However I am talking about the things you are likely to encounter on the street these days and yes you could come up against a gun and if that is the case you may have been trained how to take a gun from someone but in all honesty if it is hand over the money or try to take the gun away, I am handing over the money. Knife, same deal. Katana, Jain, Dao, baseball bat, battle-axe, man in a full set of armor on horse back with a lance. Much the same... but I will admit I might snicker at the guy in the full set of armor.
There is no one martial art that can handle every single give situation, study all the Systema you want, there is little or no defense against an ICBM. Train all the Sanda you can but I am still betting on the tank, and as a side note most Police/Military Sanda training already admits use a gun or a weapon it is more effective and this stuff is only if you have no other recourse. And in the Chinese Police and military (just like any other in the world) they also train how to use these weapons. But they do not train you how to defend against them should you be without one while training you how to use them generally, that is taught in Sanda.
What I am talking about here in this post is what has been talked about ad nauseam all over MT and similar web discussions. Kicking, punching, joint locking and grappling.
First I will say I am damned impressed by grappling styles and their dedication to training but I feel it also the height of arrogance to feel that we in the 20th and now the 21st century were the first to deal with grappling and that we know better now, when martial arts are needed less, that those that used it years ago when martial arts were needed more. Grappling is a VERY old art, oldest CMA in existence today and likely the oldest on record Pankration. So it is likely when people were coming up with various TMA styles they did consider the possibility.
Just because an art does not teach grappling does not mean they do not teach how to deal with it. But it sometimes take a whole lot of patients, which many don't have, to really learn the art they are training in order to know how to deal with these situations. Also it sometimes takes getting hurt and we don't, in general these days, like to get hurt, we all want it to come easy. And of course there are those teaching an art that either don't understand it or don't see the point of something, or their own prejudice gets in the way and the result is they do not teach the whole art. I myself have a real hard time these days with teaching any Taiji sword forms, I simply do not see why, yes it is good for health purposes and it helps internal but it will NEVER be used in real application outside of the school, you just can't roam the streets carrying a sword these days. But many martial arts are whole arts and can deal with just about anything (meaning within the realm of physical confrontation - kick, punch, joint lock, grapple and some weapons) thrown at them.
But there are without any doubt arts that were designed for very specific purposes and PLEASE don't make me reproduce that incredibly long list of world wide martial arts to point them out, that is really a pain and I think you get where I am coming from.
There are simply no absolutes. Meaning that nothing and no one is always right or has all the answer's.
Very true
But you also need to take into account just because someone else’s way is not the same as yours does not mean it will not work or it is wrong. My Taiji sifu and my Sanda sifu have very different approaches to things and they are both incredible effective. Just one is quick and causes you great pain and the other takes his time stays Disturbingly realxed (from the pov of the attacker) and causes you great pain.