"Play to earn" will never be popular, a large precentage of gamers are middle class people who absolutely don't need to collect pennies for hours of repetetive tasks.
Funnily enough, that's what actually makes the "Play to earn" games sustainable economy-wise. With people in poor countries farming in-game currency and items, while the middle to upper class people are the ones purchasing these farmed items for their own enjoyment — to either upgrade their characters, or for cosmetic purposes.