Everything I've seen from widely popular games like this suggests that the
vast majority of people play on normal or lower difficulty settings. Hardcore isn't even the "hard" setting, it's the "very hard" setting. Clearly you're just a gaming god who is finding it hard to relate to the inadequacies of regular gamers.
Edit: here's an example from Hearts of Iron 4 by Paradox. Grand strategy is
much more of a niche than third person shooter, so if anything you would expect the smaller, more dedicated audience to lead to more people playing on higher difficulties than most types of games. This isn't even % of people, it's % of total games played, meaning it's skewed in favour of super-dedicated players, who tend to play on higher difficulties.