Since we are talking generalizations here I'll throw out a few thoughts. I hope they haven't been covered (this is a long thread and I admit I haven't read all of it). Most BJJ guys I know move very slowly and work their way through each defense. In the dojo or even in a rules based sport system this is a good method. Most good BJJ guys I know are like a small stream of water; given enough time they will work their way into the smallest crack and open it up and then the whole river flows in. This method has advantages because you learn to be patient, not over commit to one attack or strategy and it teaches you to see openings everywhere. The problem is that in the field you need to take someone out quick, fast and in a hurry. Not every BJJ guy trains for that. I think for military or police work speed in breaking someone's defense needs to be a greater focus. Then again at the BJJ club I use to teach Daito-ryu out of the blackbelt teacher there submits folks VERY fast. So I guess it all depends.
I'd say the best technique against a BJJ guy is to bring a few friends with you because most BJJ guys move slowly and methodically. While he is tied up with you going through various positions of dominance your friend can light him up. Just my thought based on generalizations I have observed.
Those are good points Chris and I agree. The typically game of BJJ is careful slow and deliberate. We play our game to someone else's disadvantage. It is a VERY fun game to play! This may or may not reflect the reality of a fight. and I agree that you need to work speed, efficiency, and economy of motion. Correct, not every BJJer trains for that.
As I am a Military guy that teaches combatives as well as BJJ, we teach both. I try to show when I'd use different things depending on the conditions. For example I am not an advocate of the Mount on the street if I can control with Knee on Belly. Mount is too committed if you must move fast to get to another opponent.
It is about understanding the end states, conditions, and effects of your training. There are different decisions that you make depending on these things. You have to train as you will fight!