I think your thinking is a bit flawed as to why supposedly there aren't a number of practitioners who match the old greats. First off... There are... I can think of a dozen right off the top of my head. The talent is there although talent plays a small part. O'Sensei, Kano, Helio Gracie, John Hackleman and the "greats' all had something in common. Thier lives were/are the Martial Arts. They lived... breathed... and ate... the Martial Arts every day. Almost every waking moment of the greats were spent improving thier practice. Very few of the folks I know (including me) who practice have this this devotion but those that do can and do achieve the same level of "greatness." I submit that anyone who can devote the time, energy, and complete total dedication to thier practice WILL achieve the same level of "greatness" over time.
When I was young I was an Airborne Ranger in a Ranger Battalion. Every waking moment was spent in the pursuit of killing people as quickly and as efficiently as possible with any and every weapon we could get our hands on. Those who did not have complete and total focus on this task were sent packing to other units. The standards were simple. You were either one of the best Infantry Soldiers in the world or you were out. I submit that very few instructors in the Martial Arts have the same kind of mindset and why should they....They have lives to lead...families and jobs too.
My point with my anology is I have "tasted" what it is like to have complete and total focus on being the best at something. After three years of this kind of practice I realized that all I needed to do was apply this kind of mind/heart set to anything and I could achieve the same result.Sadly very few people I know have had this kind of life experiance. Pick any sport or any Martial Art... Apply this kind of dedication.... And you will get to the top of the mountain or die trying. That is what it takes.
Funny thing is as far as Military Achievements go being a Ranger is not the top rung on the ladder. LOL
The task is simple to define...Do you have what it takes to be the best? Are you willing to go to any lengths and make any sacrifice required to achieve it? The result is always the same if you do and can be applied to any practice you set your heart on. You will be one of those "greats."
Training methods have nothing to do with it Don. look to the heart of the man taking the training... look to your own heart... How far you go and what you accomplish is completely up to you.
If you're being taught by someone who does not have the same fire in his eye Move On...You'll find fellow travelers on the journey...If you are the one teaching well... You have an obligation to lead by example... to hold yourself to a higher standard...And to practice hard...
Cynics bore me....They are usually folks looking for an excuse not to push themsleves to be the best they can.
The "Old Greats" all understood this...They did not look to anyone else to "teach it" to them...As O'Sensei once said,
"Instructors can impart only a fraction of the teaching. It is through your own devoted practice that the mysteries of the Art of Peace are brought to life."
I'm sorry, I simply can not agree. While it is a personal responsibility to improve yourself, you should not be alone in the pursuit. This is why you train with an instructor. It is the job of the instructor to push you beyond your own personal limits and beyond your breaking point. The training method is the way this is done. Great boxers will never be made by standing in a line throwing jab, cross, hook. Great bjj players will not be made doing nothing but hip movement drills and complaint armbars. Great judo players will not be made doing nothing but randori all day.The best of the best in anything in the world have a training method that developed that skill better then the people lessor than they are.
You mentioned the Gracies, perfect example of what I am talking about. They are no longer the best at bjj in the world. Their students took the art further then they did, developed better training methods, stole from other sports and arts, and made something bigger than what it was. I'm not nearly the best blue belt in my club, but I've been to a few clubs that still train the old way and found out that I was in better shape, had better technique, and better balance then most of the blue belts in those clubs. I've been to other clubs with a even better training method then what I do, and I found I was out classed by everyone there with the same amount of experience as I. I trained in a judo club that did nothing but standing uchi komi for 2 years. Almost no randori, no moving uchi komi, hardly ever a throw line. Of course the brown belts could beat me up, I sucked at every tournament I went to. Then I switched to a gym that trains properly, with a good balance of uchi komi, strength and cardio drills, moving uchi komi, throw lines, moving throw lines, and lots of randori. A few months later I went back to my old gym, I cleaned the mat with all those brown belts. Why? I think the answer is simple. At the old club, they were doing judo, but with a training method that developed the skills much much slower than what could be done. At the other club, they were training judo in such a way to really build skill quickly in every area needed. The same is true with the ground work. In most judo clubs I've been to (except the ones in chicago), mat work is practiced like this. You are shown a pin or submission, you drill it a few seconds, then you do like maybe 1 minute of sparing. When I went to bjj, I was destroyed on the mat by white belts I had a few years of aikido, and almost 2 years of judo. Why? Because their training method was designed to produce better mat work. When I took that mat work back to my judo club, even after just a couple months, I was the "king" of mat work. Today, most of my judo partners train in bjj and have brought that training method with them. We evolved our training method to improve our abilities.
This is in stark contrast to what I've seen in my experience in aikido. I have not heard of anyone taking the art greater than Ueshiba. It seems like his students were not able to reach his level (at least that is what I'm told) and I have not heard of people reaching the levels of his greatest students even. To make matters worse, I see a lot of people modifying their training methods and techniques without ever getting in a fight and finding out how the old ones worked. Simply put, they have no point of reference to be making those changes, so the results are unknown.
But don't get me wrong, I still train from time to time in aikido. But I don't go for the work out. I go to get ideas that I can practice using my training methods. Sense switching to this method of practice, my success rates have gone up. Although my aikido instructor would probably tell me what I am doing is not aikido, and maybe even that I have no right to do it.
And yes, I really think everyone can train as I do. I'm not a jock. If I can do it, I can't see why anyone can't do it. Maybe a little more or less intense, or more or less often, but it can't be done.