Good insight!
Not surprising, as BJJ was developed primarily for sport and not combat.
A lot of martial arts as taught in the States, most especially in the early years of personal discipline, and definitely as taught when involving younger students, is not combat oriented.
I've a brother in his mid-60s who teaches martial arts and who does a good job explaining the differences.
I've only a very minimal experience myself, mostly consisting of sparring with said brother when I was in junior high and high school. Combat martial arts of whatever flavor isn't interested in grappling and holding an opponent in good sportsmanship. It's interested in flat out ENDING a fight.
Bones break, joints dislocate, eyes lost, throats crushed, kneecaps dislocate, muscles cramp and lock up, blood flows, brain is concussed...it's very much an application of deadly force. And fights involving this level of physical combat tend to be very short.
Not saying, of course, that sporting martial arts isn't useful. But there's a big difference in training and mindset in being taught a sport and taught combat.