In my opinion it wasn't the death of Tom Clancy, bad decisions by Ubisoft or anything else like that that caused The Division to fail shortly after launch. The real reason that The Division failed miserably, is because it simply wasn't fun anymore after you finished the main campaign and then played around in the DZ a little bit. After you hit max level (30 at the time) in The Division, there was literally nothing
left to do except spend days
grinding and rolling for the "perfect" gear that wouldn't even be relevant once the first DLC hit. Not to mention that by this time everyone had figured out that the risk / reward for actually killing another player in the DZ was so outrageous that all PVP in the DZ stopped and people only used it for grinding. Since the DZ was handled so poorly, the PVP wasn't even fun or engaging, and the PVP was the only thing awaiting maxed out players once they finished the game. So without that, there was no drive to continue playing the game. I pre-ordered the "Gold Edition" of the game that came with the season pass, and honestly I never even went back to try out any of the DLCs. That game was ruined for me after being such a massive letdown following the ridiculously cliff-hanger ending of the main story.Tl;dr:
The Division failed due to poor game design and a lack of truly engaging "end-game" content. Nothing more, and nothing less.