You could make everyone but one person above average by making the rest equal. Making them all better than average is still possible, but it takes an infinite number of people. If you have one person with an IQ of 200, one with an IQ of 150, one with an IQ of 133, one with an IQ of 125, etc. so it approaches 100, the average IQ is 100, but everyone has an IQ higher than that.

You could make everyone but one person above average by making the rest equal. Making them all better than average is still possible, but it takes an infinite number of people. If you have one person with an IQ of 200, one with an IQ of 150, one with an IQ of 133, one with an IQ of 125, etc. so it approaches 100, the average IQ is 100, but everyone has an IQ higher than that.