I just checked up on it, because it’s a number I remember reading earlier. What I have noticed is that when the 75% market share is mentioned, it’s downloads, that’s a pretty meaningless number. The only number I could find was 18% SALES from 2013. No doubt that has increased in 11 years. I corrected the number to 20-50% since there is no way it can be 75% with several of the biggest game developers like Microsoft, EA, Epyc and others almost completely avoiding Steam. Together with independent sales, and Epic and Microsoft store, and smaller outlets like GOG and Humble Bundle.