Why is it that everyone believes that UFC fighters are the best?

Every match I have watched I have seen the same thing the two opponents swing and get winded not even lasting or doing any better then the average fight time and to say they are the best is way out of line. There have been accounts where they say Bruce lee was their inspiration well Bruce Lee was the best we had observed in America there have been better fighters before that and still alive and kicking are the Shaolin monks who train their entire life.