Why MANY smart people are not social?

What's your definition of "smart"? The inventor of the most influential English-language IQ test acknowledged that his test did nothing to estimate a person's social skills:

"There are, however, certain characteristics of age scores with which the reader should be familiar. For one thing, it is necessary to bear in mind that the true mental age as we have used it refers to the mental age on a particular intelligence test. A subject's mental age in this sense may not coincide with the age score he would make in tests of musical ability, mechanical ability, social adjustment, etc. A subject has, strictly speaking, a number of mental ages; we are here concerned only with that which depends on the abilities tested by the new Stanford-Binet scales." (Terman & Merrill 1937, p. 25)

Interesting article, however it seems to suggest that these 'Smart and social' people are not on equal footing when it comes to intelligence as the 'Smart and not social'.

However your box graph suggests they are.

The points you make a good and solid but it doesn't really bring out as to why the perception suggests there are many less 'smart and social' people than 'smart and not social' people

Soon as I visited your site and had the content I expected covered up with an overlay, I closed the tab and lost interest. Your visitors don't care about the other 1500 articles you have on your blog, but they do expressly care about the one they are trying to read at the moment.

In other words, MANY smart people are introverted.

The book "The Introvert Advantage: How to Thrive in an Extrovert World" came to mind when I started reading this.

I've noticed when one part of someone's personality is really well developed they let it compensate for not develop other areas, be it mental, social, emotional, or whatever; instead of being well rounded.