You're somehow assuming all computer games involve grinding for some 1% drop.

You're basically describing old single player games that did rare drops to pad gameplay time, then the first MMOs where grinding was there to keep you paying for the subscription, and now the IAP fests where the grinding is there to make you pay something.

However, there still are games that do not involve grinding out there. Even some AAAs. You do not have to be predatory to enjoy some success making video games.

Edit: I missed that: "Even if the hours played and enjoyment received are perfectly equal."

They aren't equal. Do you call grinding for rare drops equal to enjoying a story or developing and applying some skill?

And how is hours played a metric of enjoyment? If you count hours played, the game i spent the most time in ever is Minecraft. Paid all of $20 for it.