Again, i can see your point and i dont desagree. Let me give you an example, something i dicover.
The first time i got to the catch class, i saw different people, all catchers no bjj guy. So here i am, 2 years of mma, not a bad dude on groud, ok cardio ect. We did some drill, learn 1 tech, drill again and the last 20 mins, it's time to roll a little bit.
I'm 5'9 190lbs, short legs, good balance (it must have some advantages to be small! ;-) ) Got matched with a 160lbs man. So i was thinking ' he better to be good' and we start to roll. The first thing i've noticed : He didnt react like i was used to, i was not supposed to be there, or make me think a lot more than i'm used too. He simply took me out of my normal game. After 3-4 months now, guy who i train with already see the diff in my game. Just little things, here and there, some positions, some tricks ect...
That make me think, it's not just catch, just the fact that i did go train elswere, probably add some things to my game too. New coach, new partners ect...
That's what i'm talking about beeing open minded, sorry if i insulted you, sometimes the words didnt came as right as if i was talking in french.
Have a nice day