What is "combat"?
I thought it might be a good idea to distinguish between street brawling, self defense and actual life-and-death combat.
In a one-on-one fistfight, you might decide to do some ground grappling. This is typically about proving who's tougher. You may get some interference from the crowd, but this isn't necessarily influencing your tactics. You can lose and live.
In a self defense situation, you want to decisively end the assault, avert the robbery, etc. and basically escape. Going to ground willingly is probably not a good idea because it's assumed you're against more than one opponent. If you lose you might die.
In a real combat situation, guns and other deadly weapons are in play and no tactic or technique is off-limits. You'll be killed if you lose.
Brazilian Jiu Jitsu dominates the first situation and tends to win the argument about who's the toughest individual. But you're a football for the second, third, etc. opponent.
Krav Maga is combat style fighting. It's about killing deadly attackers.
Aikido is great for things like bar bouncing. Get control of a person or situation with the minimum amount of scuffle and injury.
It seems vital to have more than one skillset up your sleeve. I hear O Sensei did.