DDO has never hit anywhere close to 1 mil subs. It was hemorrhaging thousands of subs until the f2p model essentially saved the game.
The best source I could find. From the now defunct mmodata.net.
We all know how to keep players at cap. Its been done in the past (eberron unlimited). Create new raids/loot without invalidating old raids/loot. Its that simple. Removing raid timer bypasses and the best tomes (currently +8) from the store is a necessity. Unfortunately it will never happen.