Prior to widespread use of the Internet, development and growth of Pete's board and the rise of E-Bay....very few people ever traded or sold their points to people outside of their own friends and acquaintances. This type of activity is something DVC never dreamed of when they first started selling Disney Vacation Club.
I never knew about renting or trading until these boards, so unless you knew another member prior or had a friend that wanted to rent your points, I don't think there was an avenue to rent/trade.
Yes, you could and still can "trade-out" through DVC, but for the owner the deal really isn't that good. Renting/Trading here has been much more beneficial to both parties.