I do not think that Dovetail would Give up TS2021, considering most of the revenue they get comes from that game. I think that TSW will have 680 DLC items (In 2040) when TS20XX dies. Come on, it is based on the 2007 game RailSimulator. If it has lasted this long, than it is here to stay
It will remain as long as it makes them money. It's as simple as that. Just as Counter Strike remains viable for Valve, and World of Warcraft remains viable for Blizzard, TS20xx will remain for DTG as long as it is viable, and that is determined by how many people use it. Both CS and WoW are ancient games. The results of this poll are hardly surprising though, as it was asked in the Train Simulator forum. Ask it in the TSW form and you'll probably get a different answer, and none of them will be based on pragmatic considerations, but rather personal opinion based on preference for one game over another.