Currently all I have really seen of some player interaction trading is base resources. An economy of laziness for lack of a better term. It is just based on what higher levels dont want to do themselves, like gather mushrooms or something. Which is fine to an extent for the poor and lower levels to have a way to money. But it seems to end there and that is due to the way gear works and lack of PVP.
From what I have gathered gear drops are tailored to the skills you are using at the time. I switch to fire magic and suddenly I get gear tailored to it. While nice early game this is very bad and detrimental to an economy. It has turned so much gear into vendor trash. Even though there seems to ve different rarities it is just trash. Why buy something from someone knowing you will get something just as good if not better as loot? Gear drops need to be more random and not just for you to use, so you can trade with others. The point of an MMO is to interact with others afterall.
Lack of PVP is also a crucial detriment to an economy. Like it or not it is a core to MMOs. Now I know this community gets triggered by PVP talk but it is needed. Dont get me wrong it doesnt need complex pvp like ESO. Runescape style with full loot and a pvp zone would do just fine. Balance isnt hard as long as each method is viable. You could even work in some gear bonuses against certain damage types so you could build to be a fire mage killer then shit yourself at the sight of an ice mage. It wouldnt be hard to have such basic pvp.
As fot how PVP effects PVE, well that is simple. If you have a group that doesnt like skilling and only wants PVP they have to buy gear from the PVE people, enhanced vy full loot pvp. It is wonderful to have the world go around like that. If a game is too much PVE you end up with a community of blacksmiths trying to sell each other swords, it doesnt work.
Im not saying it has to be added now, there is still plenty to do witg PVE. Just nearing the time for full release PVE should be done enough for this basic PVP style to ve added. The plan has to be there, rather than just we are skipping pvp. Too much PVE and you have a co op RPG not an MMO.