I've been educated in this subject lately. I went back and watched some early UFC. UFC 1 infact. What I discovered is that the UFC you see now gives you a false sense that "anybody with boxing skill can bang" and might have a chance in a UFC ring - when what really happens is these guys get put on the floor where they have not a single clue how to defend themselves. They never get anywhere. They look confused and end up tapping out pretty weakly.
I'm sure fighting will evolve to the point where everybody knows to have a well rounded game, even if you're just a weekend warrior but right now, if you have jujitsu and can avoid a few early punches, you're probably going to be able to defuse most encounters with idiots who believe due to a few hours of boxing, that they are invincible.