The article is talking about our image of "successful" not "smart".
Articles like this will perpetuate that belief. Bad soft skills? Lack of a structured lifestyle? Cannot focus? Many people will relate to these because they take effort to build.
Though Wilson touches a good point. Medium levels of intelligence is require for most jobs, even in Investing you do not need to be that bright to be "the best" in the field. Additionally, we know now that novel ideas comes from a background process in your brain that takes a lot of time and domain knowledge to develop.
At the risk of kicking off a debate to define the word “intelligence”, I think you’re massively underestimating the intelligence - not just effort and experience, but actual intellectual horsepower - poured into the upper echelons of investing strategy.
More generally, while I agree with your overall comment I’d say there’s likely few fields where the best professionals aren’t extraordinarily intelligent in addition to other success-amplifying qualities.