It is more about modding outside of the general player base that already played, and dropped it.
The sustained users are ones that have good mods that improve the AI, and other aspects of the game. Civ 6 hasn't released the DLL, so us as modders, are in a holding pattern. Most of the major modders have quit (as have I) until the DLL is released.
As an AI modder, I just can't improve the AI without the DLL.