Yeah, I have to say that the evolution of leg locks didn’t change or break the core principles of BJJ. What it did was add additional options to a simplified tactical rule of thumb that was based on those core principles.
BJJ has always been about finding advantageous positions so that you can control and harm an opponent and they can’t control or harm you, then use that positional control to end a fight by striking, strangling, or isolating a limb and breaking it.
The old simplified tactical rule of thumb was that you achieved that goal by taking someone down, getting past their legs to control the upper body, then applying a finish from there. The newer understanding is that properly applied leg entanglements can be dominant control positions just like side mount, full mount, or back mount. The principles haven’t changed, we’ve just learned more control positions.
BTW, this process has also developed in parallel with the understanding that submissions in general can also be dominant control positions in their own right, even if you don’t manage to finish the submission.