This is great for the “game GDP”, a specialized miner and ratter surely kill more rats and mines more than two guys who both mine and rat. But games are not real and “game GDP” has no value. Devs can create anything from thin air. Games should be entertaining and/or challenging and grinding the same task optimally is anything but.
On top of this, there is RMT and official token trade, ergo there is a class of players who produce nothing but open their wallet to give money (or gametime) to other “players” who farm for a living. With that comes botting and hacking and all kind of nastiness.
The blunt solution is soulbounding. You can’t trade anything in World of Warships or League of Legends, even illicitly (besides full accounts). This is fine for a competitive FPS, not so much for an MMO. People want to form groups and play together and that includes economic cooperation.
I think the solution is to allow groups (may they be formal guilds or pickups) to utilize resources as a group, letting individual members contribute and get rewards, while personal items cannot be traded (nor the materials coming from them).
For example the guild needs a raid buff altar, so miners can farm stone for the construction, gaining “bonus loot” rolls for all-guild raids. Or an EVE ratter can contribute to some automatized SRP fund and in return gets credited on every kill report the ships he paid for were present.
The point is to disallow one player to give/trade anything to another player what he can individually use, but allow them to give/trade items that are used as a group, together.