Something that I've come to realize is that as a practical matter, intellectually gifted people who haven't developed very strong ability in a quantitative subject tend to be at a major disadvantage relative to those who have. The quantitative subjects that I have in mind as "quantitative subjects" are primarily math, physics, theoretical computer science and statistics, though others such as electrical engineering may qualify. [1]

This point is usually masked over by the fact that people who don't have very strong technical ability are often reasonable functional by the standards of mainstream society, and don't realize how far they're falling short of their genetic potential. They tend to have jobs that don't fully use their strengths, and experience cognitive dissonance around being aware on some level of far they are from utilizing their core competencies. 

Consider the following:

• The Google co-founders met as computer science graduate students at Stanford. Sergei Brin double majored in math and physics and was an NSF graduate fellow. He comes from a mathematical family: his father was a math professor at University of Maryland. 
• Bill Gates took Math 55 as a freshman at Harvard, which is the class designed for the most mathematically talented students at Harvard. During his sophomore year he did research which he later published a paper on with well known theoretical computer science professor Christos Papadimitriou.
• James Simons comes close to being the only elite mathematician to leave academia for the business world. He founded the hedge fund Renaissance Technologies and made ~$12.5 billion.
• Charles Munger, the Vice-Chairman of Berkshire Hathaway (net worth ~$1.3 billion) often quotes the maxim of the 19th century mathematician Carl Gustav Jacob Jacobi Invert, Always Invert, and characterizes him using that concept to solve difficult business problems 

I can't give a brief justification for this, but I have good reason to believe that the ~10000x+ differential in net worth comes in large part  from the people having had unusually good opportunities to conducive to becoming very technically proficient, that resulted in them developing transferable reasoning abilities and having had an intellectually elite peer group to learn from.

I know a fair number of brilliant people who didn't have such advantages. The situation actually seems to me like one in which amongst intellectually gifted people, there's an "upperclass" of people who had opportunities to develop very strong technical ability and an "underclass" of people who who could have developed them under more favorable environmental circumstances, but haven't. Many intellectually gifted people who didn't have the chance to develop the abilities mistakenly believe that they lack the innate ability to do so. And people who did have the opportunities to develop them often look down on those who didn't, unaware of how much of their own relative success is due to having had environmental advantages earlier in their lives.

[1] James Miller points out that graduates of elite law schools may have analogous advantages – that's a population that I haven't had exposure to.