I don’t know about you, but when I walk around and see people and talk to people, I can definitely tell that there are people more intelligent than others ... so if I can tell, without any measurement at all, I’m sure others can come up with a measurement.
BUT ... perhaps your particular experience is that all people you have met and come across are of all the exact same intelligence ... :-) ...
I can assure you that it’s definitely not my experience.
Clearly it is not uniformly distributed.
Did you know that 50% of the population has a less than average IQ? That’s how Obama got elected twice.