Another thing too though is that there is no universal agreement on what "the basics" are. People say things like closed guard armbars are basic, or knee cut passing is basic. I would not even take the definition that far. The basics are the underlying principles that make everything work. No matter if it's a closed guard armbar or a berimbolo. Both are built on a foundation of basic principles. And they definitely change like you point out.
But when people say Roger would be fine because of his foundation/basics I don't even think they're talking about the specific moves that he uses. There are just simpler things and ideas. For example, good posture and proper body alignment exists in all aspects of life, and in all positions in BJJ. So looking at that basic principle, Roger's mastery of those kind of principles is so solid that it doesn't matter what technique or move he's using or what technique or move he's defending. He's always going to be in perfect or close to perfect position, and he's almost always going to have his opponent out of perfect position.
So the moves/techniques can be anything, but as long as Roger is in better position than his opponent or close it to, then he is going to win or at least look pretty good. Both of those options are likely.
Concepts like this are why Marcelo could have matches or roll in the gym with guys that were experts in techniques that he never used, and Marcelo was able to not end up caught in those positions unless there was a large gap in physical attributes like size.
I hope that wasn't too weird.
