I think a big issue as well is that games are made for 10 year olds. When last did you play a game on Brutal (usually the hardest setting) and think... this is kinda easy. Starcraft WOL's last few missions took me weeks at a time on brutal. I'd have notes to when to do what and when other things would spawn. It was a challenge. In contrast I cleared HotS on Brutal within 2 days, feeling disappointed.
A lot of games since just wasn't a challenge.
In the old days, finishing some games on hard was really an honour, because they were just that.. HARD.