While really well stat’d ancestral rares will be sought after and worth trading for… the fact of the matter is…what is there to give in return for the item that the seller (trader) would want?
Gold? Gold is infinite, while it is needed now, it is also very very very easily farmable. There is no other currency or commodity in the game that is highly sought after or wanted that could support a trade economy.
Enabling the trading of Legendary items, Unique items, and Aspects, would certainly help. But it still doesn’t resolve the matter of there is no high trade currency or commodity to help sustain a trade economy.
I also have a post on the topic here, that was having a discussion on the matter at one point.