Blaine
Cis-Het Oppressor
Let's not buy into this tripe. The vast majority of 'difficult' games don't test mental ability, they test bloody-mindedness and the quantity of free time the player has.
If you beat a really difficult game, it isn't because you're a wunderkind, it's because you have nothing more worthwhile to do with your hours.
Should I buy into your oversimplified tripe instead? You should also specify what games you're referring to, as RTS, mobas, flight simulators, twitch shooters, and so on featuring steep learning curves and high skill ceilings can and do test mental acuity, memory, foresight (anticipating moves in advance a la chess), hand-eye coordination, reflexes, dexterity, rhythm, et cetera. I'm going to assume you're mostly referring to sedentary games such as RPGs and turn-based/grand strategy... although your statement isn't even particularly true of turn-based/grand strategy games, since many of the respectable titles in those genres are also genuinely mentally challenging.
So pretty much we're referring to RPGs, here.
I dislike being able to muddle through a game doing whatever I please, winning and making progress regardless, and not being particularly challenged in any way. It's extremely noticeable, especially in RPGs. It does often take longer to complete a difficult RPG, but does it really matter if Game X takes ten or twenty more hours to beat? What's the rush? There's no need to finish a game as quickly as possible. Hell, the longer a good game lasts, the better. Why the "I just don't have enough free time not to casually have my hand held"/"herp, you live in a basement" rigmarole?
I tend to get that "you have nothing worthwhile to do with your time" garbage from the same people who agonize over a $30 game purchase. Meanwhile, I have a career that pays in the low six figures and can afford to blow thousands of dollars on Kickstarters.