If I'm reading your post correctly, you're referring to ground grappling, only. When I refer to grappling, that includes the standing work (takedowns, etc.) - in fact, we're (NGA) far more predisposed to standing than ground grappling.When you are dealing with multiple opponents, the grappling is not a good approach. I still remember that onetime my Shuai Chiao teacher got into a fight in an office space against 7 guys. He used mainly elbow in the whole fight, no punch, no kick, no lock, no throw. This is why I always have faith in "elbow". You may not have enough space to punch or kick, but you will always have enough space to strike with your elbow.
IMO, the striking and grappling integration is used mainly in 1 on 1 situation. The moment that you put yourself on the ground, you lose your "mobility". This is why one should also train take down and take off at the same time. Even you take your opponent down, you don't have to go down yourself.