Perhaps of interest:
https://www.chess.com/article/view/can-anyone-be-an-im-or-gm
Also:
What It Takes to Become a Grandmaster by GM Andrew Soltis
What is the proper training to become a grandmaster?
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There are, roughly, 7.5 billion people in the world... Of those 7.5 billion, about 800 million play chess. However, of those, only 1621 are FIDE official GM's as of 2018. The Crisan method is a joke btw. Crisan, somehow, falseified his rating without any verifiable evidence to support it, and was later exposed when he scored a .5 out of 9 in a FIDE official tournament. The games were analyzed and it was agreed upon that his rating of 2635 must have been a fraud. He was then stripped of GM and IM titles.
Bumpy di do dimpy di bumpy.