Sure its a plug but heck, its frustrating when you plug all day and night for 5 years over this and people still say that its almost impossible. Collating all the maps together has traditionally been the hard bit and making the maps is the fun and easy bit - its just that there would be an awful lot of them to do. In the past, like say Forgotten Realms, the creators have produced many maps of the same place at different scales. A) This is a waste of time and effort and B) They never really lined up seamlessly. Also, people would generally independently make very similar maps of similar places like inns & castles whereas what you need is templates of maps which could be chopped about and modified. So given that these three issues can be eliminated the actual difficulty can be significantly reduced to a manageable level. Add on multiuser networking etc and its all there for the taking.

If you had written Photoshop and people kept saying that its almost impossible to make maps with MSPaint then you cant help going Aaaarrrrhhhh !!! The undertaking of making a continental sized campaign world down to floor plan level seems daunting only if your sat there with a pen or a paint package contemplating the enormity of the task ahead. If you change your perspective on how to deal with the problem then its doable. Not easy of course but very possible. The talk of it petering out after a certain time is a nonsense if you are not making the map like writing a book starting at page one. Everyone could continue to make the maps they already make and it would still progress. Nothing has to change - it just needs collating into a campaign. The most change would be that sometimes you might have to make a map of a more specific area because its missing. The idea of GTS is to do away with even that by generating a base land that has everything already there but not populated.