I think one of SE's problems is they dont like being offered help, or getting outside support. If it came down to it they'd have 1 guy doing everything just to ensure everything done in house by their employees.

A lot of other big MMO's borrow engines from companies who dedicate themselves to building and use a lot of community support, for example TERA is built in the Unreal Engine, so they didnt have to make the engine they just mod it, which anyone who is an UDK expert could probably do, just add more people onto it and it gets done quicker. Aion runs on Crysis 1 engine, which is freely available thus it was easy to mod up private servers and emulate scripts using Java. But even XI to this day doesnt have a fully-retail like private server and is still getting developed on by various people as it has no grounds.