If the goal is to have the best skillset, then I pretty much win with my ancient stuff. I can fight with a staff. That's a fighting skill set. Take those skill sets and I'll have a knife. Throw away all of that and use a gun then I still win against modern BJJ. So when you say "Best skillset possible" then BJJ wouldnt' be better than me with a gun. Or me with a staff.
Ancient people did more manual labor than people today so they would have been very strong. It would be difficult to be weak if this is your daily workday and this isn't even warrior training.
Science has helped us in with some areas but not all. Having science on your side doesn't make a person a good fighter by default. I'll pick the ancient spartan who has fought for his life multiple times in hand-to-hand combat over the best MMA fighter of today.
When you said loyalty. I'm thought you meant "blind loyalty." Where everything must stay the same and that new teachers can not add their experiences and improvements that they learned about the system. For example, If I learn another application for a Jow Ga techniques that makes it impossible to be taken down (extreme but needed for the example), but I don't use that technique because that's not what the original teachers taught then that I don't agree with. I say this because I use a punching technique as a grappling technique against a front kick. I've had success using it and it allows me to hook the kick and throw my opponent off balance onto the floor. To my knowledge no Jow Ga teacher that I know of teaches this technique. I'm not saying it it's new but for me, this is like a new Jow Ga application for that punching technique. I only say that it's new because I've don't know any Jow Ga teacher that teaches to use the punching technique in that way. I learned this by accident so it's not like a great mind at work. But for me. that's my application and my contribution to Jow Ga.
I also do sweeps from a high stance. Again Jow Ga doesn't teach this as far as I know of . I "developed it" through Jow Ga without any influence from any other system. I simply wanted to do a more mobile sweep that works well against a boxer's footwork. The end result was this sweep. I found that the lower sweep was too static for me. Even if the sweep is quick, it doesn't have the ability to pursue an opponent. The sweeps that I've developed allow me to use them to chase down an opponent tor to retreat if needed. It would be stupid for me to discard these simply because the old teachers didn't do it that way. I'm not like that and I don't think the founder would appreciate me finding away to use a technique in another way. Martial arts in general has never stayed still like that in terms of development. Does it make me a better fighter than the founder of Jow Ga. Heck no. For starters I don't even train like a fighter so how am I going to be better than someone who trained it and used it in a life and death situation. Jow Ga is the combination of 3 other martial arts systems, so for me not to continue to develop Jow Ga would be stupid considering how Jow Ga was created.
Literally the founder knew multiple martial arts and he took what he like the best in each, based on his ability to do them and created a hybrid system. If that's not development then I don't know what is.