This is a good take. I never really thought about it like that before, but I am definitely a little bit harsher on old school techniques than new ones. You pointed out a bias that I didn't know I had.Yeah I can totally understand putting a low priority on the knee in the butt guard break in a curriculum. I even understand leaving it out entirely.
What I don't understand is calling it completely wrong and saying it should never be taught anywhere. That seems excessive.
Marcelo famously dislikes the kimura. Does that mean no more kimuras for anyone? I mean Marcelo would know better than just about anyone else what works at the highest level right?
We also seem to apply the empiricism argument much more harshly to moves perceived as being old school. The berimbolo is less popular these days, but only a few years ago it was all the rage.
If we really look at it, the only guys having massive success with it at the highest level were small guys featherweight and below. It could even be argued that it was only two sets of brothers really dominating with it.
Because of this, some people didn't want to focus on the berimbolo much and didn't teach it. That was fine. But I don't remember anyone saying the berimbolo was an utter crap technique at the highest level because it only worked if you had a brother ~140 lbs or so to drill it with.
Also re: the two sets of brothers...I would even say that Gui didn't do very many berimbolos. or at least not all the way to the back. he seemed to sort of drop people down and come up into leg drags or knee slides. So really you're looking at 3 legit berimbolo killers at the highest level.