Because singers make a lot more money than inventors, celes ;]

Genius level IQ is much lower than 180. Try somewhere in around 140, where Einstein was :]

Also, I don't think anyone has taken the Intelligence Quotient seriously since the 1950s when the US government were trying to recruit the best men for their anti-soviet think tanks

Has anyone here read the Andromeda Strain? it's set around that time, and is so backwards it's funny xD

Aside from all that, it wouldn't surprise me if more pop celebrities were wiser than they put on. I mean, people can't be that dumb, can they?