I think the state of Oblivion Remastered on release is a big reason for the player count drop off. The game is an absolute mess and requires the mods to fix known issues from the original. The difficulty slider has been a big issue for players on the forums, a🦂s well as known bugs like not being ꦰable to finish the vampire cure quest. The Devs should have taken a lead from the Count of Skingraad. Aka, they 'Need more time' spent fixing the issues in the game.