Not every 7' tall person is a great basketball player, and not every great basketball player is 7' tall.
With all due respect, what you say is a consummate example of "dangerously bad idea that makes a good sound bite". Most mathematicians out there are not Hilbert, Gauss, Riemann, or Euler. They are reasonably smart people that work hard over long periods of time to learn their craft and their field, and make incremental progress in the niches they specialize in.
Most people can be productive mathematicians, they just don't believe in themselves.
I doubt most people have the desire to be productive mathematicians, which is as required to be a good mathematician as being 7' tall is for playing basketball (aka not actually required, but big help).
"Most people can be productive mathematicians, they just don't believe in themselves."
Most people can X if Y, where Y is not the usual case. Again, believing in yourself, having the desire to be great at something, etc, are all included in the extremely large set of factors which determine whether someone will be good at any given activity. To say a large portion of the population can be good at some activity, knowing full-while that they do not possess most of the helpful attributes, is disingenuous.
In fact look at any list of the greatest basketball players of all time. Very few of them are 7' tall. Now look at a list of pro basketball players over 7', most of them are middle of the road journeyman players most people haven't heard of.
With all due respect, what you say is a consummate example of "dangerously bad idea that makes a good sound bite". Most mathematicians out there are not Hilbert, Gauss, Riemann, or Euler. They are reasonably smart people that work hard over long periods of time to learn their craft and their field, and make incremental progress in the niches they specialize in.
Most people can be productive mathematicians, they just don't believe in themselves.