To me, basically, when you're younger you get into the game more, a lot more of your mental faculties get invested, and you are more aware of the nuances of the game. You can comprehend what it takes to play on hard and you have the patience to do so. I'd argue the experience is more immersive, and more engaged.
When you're older your mind is full of ass and stress and Donald Trump, and you just can't give a shit anymore, and you're more concerned with making sure you didn't waste your money than having your mind blown (not even possible anymore) by a game, lol.
That's my negative take on it. And speaking of negative takes,
Cringeworthy thread title
Sincerely, grumpy old 29 yr gamer, used to be cal-i at cs 1.6 and recently picked 'normal' difficulty on Witcher 3, and questioned my existence. But at least I still play Doom on Hard, when I can be arsed to sit down and play /humbug