I think Mensa is on the lower end of high IQ societies. IIRC. I think they accept people who test in the 135 range, which is uncommon, but not horribly so. Like in the 2% range. So, 1 in 50 people. There's another group called the Triple-9 society which only takes people who test in the 99.9% percentile (hence the clever name).

Mensa and other high IQ societies consist of people who have enough time to dedicate to being in a high IQ society.

That should tell you enough about the motivation and mindset of the people in it.

Like everyone there was probably technically intelligent, but they've convinced themselves that that alone was enough to lead them to the land of milk and honey. Like they say, hard work beats talent when talent doesn't work hard. Being intelligent isn't enough, you have to acquire knowledge and you have to apply that knowledge.