Well it's not as if it's only dead "now" lol, NWN community was pretty much on the brink of extinction five/six years ago; it's just still on life support. Which is a pretty good run, but ultimately while that 'aftermarket' is fun for us but I think it'd be a hard sell from a business perspective because of it's [lack of] return.
On one hand, it did probably help keep people invested in the game which would boost sales of the two expansions and multiple DLC modules. But on the other it requires a lot of support, it's giving away for free something that you could sell, and it can cannibalize/displace sales of future titles.
I think some sort of marketplace or venue that gives players the ability to support both the developer and the content producer ('profit sharing' essentially) is the best way to make it worthwhile for both parties, kind of like the Steam workshop in TF2 or DotA2. The best analogue would be the map stamps, but unfortunately those haven't been particularly successful compared to the cosmetics market.