In my Krav Maga class, my instructor had us go against 12 opponents one at a time and then 12 opponents all at once. My instructor asked the class why we could fight 12 people one at a time but not all at once, and we had no answer. He told us to go home and think about it. I have not been able to come up with an actual tactical analysis of the difference between 12 people all at once and 12 people one at a time. I can only say that it is easier to fight 12 people one at a time, without much of a tactical understanding of why (after all, 12=12). Can anyone here help?
Because it is difficult to respond to multiple things at once
It is incredibly hard to respond to multiple things at once. If two people are punching you, trying to block one will do nothing about the other punch. Trying to dodge one just might dodge both, but might drive you straight into the other.
This is the primary factor. It is very hard to respond to more than one thing at a time.
Because more people can do more things.
Related to the prior item, more people can do more things at once. If you are fighting 3 people at once, they can do 3 attacks at once in response to your one.
Because additional people can come at you from additional angles.
With minor, temporary exceptions for specific techniques, you generally want to face your opponent. When there is one, you can generally do that most of the time. When there are more than one, especially if they are even somewhat coordinating with each other, one of them will almost always be able to come at you from a side and possibly even from behind you. This is a major advantage to that attacker.
It is of course possible to fight more than one person at a time and win. Plenty of real life examples exist. But it is dramatically more difficult than fighting the same number of people one on one. If you are doing several fights in a row, you have to contend with fatigue and possibly cumulative injuries. But if you are fighting them at the same time, you have to contend with fatigue, cumulative injury, trying to address more than one thing at a time, trying to address more than one angle at a time, and the fact that the other side can simply do more than you.