"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.
As someone who played several games at the very competitive level (World of Warcraft) and games with complex economy (EVE Online) and made very decent amount of money with both of those, I say that you are wrong there. Anyway, time will tell regarding play to earn concept and in the end, play to earn is more than just some mindless grind for pennies.