Gods, I remember the ol' Gold Farmer days. I played through the second expansion right until just before Mist of Panderia or whatever... and I recall many folks cursing the gold farmers.

But, yeah, to your point... I think you're absolutely correct. There are a LOT of 'play to earn' games that are objectively bad games, and they will rise and fall over and over. Something like the Gold Farming economy isn't likely to form in PtE games any time soon.

Edit: Whoops, forgot I was on this account lol, should have posted from @oblivioncubed. OH WELL.