science

... Did you read your own link?

Not only are mostly all of the "citations" (hyperlinks) to this random website you linked just news articles (many of which don't have actual citations or referenced research papers that are from the 21st century, or are articles from the 20th century), but some are heavily biased (quoting Jeff Bezos in the Washington Post, which he owns).

Even the website auther themselves sometimes admit to their flawed analysis, such as equating SAT scores to IQ rather than an actual IQ test. Quote:

Cognitive ability: For the first time ever, we just happen to have publicly known IQ data on every single living self-made person who was ever ranked as the richest American. As mentioned above, Bill Gates reportedly scored 1590 on the pre-1995 SAT, equating to an IQ of 170 (see chart at bottom of this article). 

Jeff Bezos told The Washington Post he scored 1450, which equated to an IQ of 146. 
According to biographer Walter Isaacson, Elon Musk scored 1400 on the pre-recentered SAT, equating to an IQ of 142. 

According to his sister Doris, a woman administered an IQ test to Buffet at age 10 and he scored a couple points above 150. However back in 1940, most IQs were still calculated using the age ratio method meaning a 10-year-old who performed as well as the average 15.2-year-old, was developing at 152% his chronological age and thus assigned an IQ of 152. Although this method (normed entirely on whites) formed a Gaussian curve from IQ 50 to 150, the mean and SD were 101.8 and 16.4 respectively, a little higher than on most modern scales where the mean is set at 100 and the SD at 15.
Converting to the modern scales gives Buffet an IQ of 146 (U.S. white norms; also 146 on U.S. norms).

Or here, quoted:

But Stanley suspected a self-reporting bias was inflating the numbers since “A students” were more likely to recall their score than “C students”. 

But most damming of all, is that this whole weird blog website is talking about a correlation between income and IQ, NOT that IQ determines income.

Correlation isn't causation. And it's no surprise that people who can go to good schools, don't have to worry about food, etc, do better on a test, but that doesn't necessarily mean they are inherently biologically more intelligent.