I think people who have a healthy relationship with games agree with you, but for me, the obsessive grinding only made the games less challenging/fun, with no reward except larger numbers on the menus-- like if the reward for the Marshmallow test was just that you got to look at a bitmap of a pixelated marshmallow on tv.
Videogames are not all bad, and of course there are many healthy and successful people who enjoy them and appreciate them as works of art. But for me personally, I regret that I spent so much time doing busywork for an unpaid job that I didn't even enjoy.
The Marshmallow Test looks kind of classist, or even racist (not sure if "racist" is the right word for it, maybe "orientalist" would be better).
Yes, if you live in Stanford or in a country that has an institution like Stanford then most probably "passing" the marshmallow test means waiting for a longer period in order to get twice the reward, but I dare say not a lot of countries/societies afforded that luxury until not that long ago (many of them still don't), in their case waiting for longer in order to get twice the reward might mean that you'll be dead by then, or evicted, or you had to escape the communists/the criminal right-wingers/the islamist beheaders/what have you.
People who are good at grinding would probably ace the so-called Marshmallow Test:
https://en.wikipedia.org/wiki/Stanford_marshmallow_experimen...