In my 30+ years of DMing, immensely more have failed after a few sessions than got to a satisfying conclusion. That's probably because my reach has exceeded my grasp. Unfortunately for the purposes of this thread - I don't remember the failures as much as the successes.
These are a few from the past few years:
Warhammer Fantasy 4e: The Enemy Within (the wrong group at the wrong time in the wrong system with the wrong campaign)
Call of Cthulhu: Tatters of the King (early TPK)
D&D 4e: H1-E3 Orcus Campaign (even just running "highlights" it was too slow)
D&D 5e: Princes of the Apocalypse (I later did the campaign with another group, but the first time it fell apart because I broke up with my gf and I was running this with her family)
These are a few from the past few years:
Warhammer Fantasy 4e: The Enemy Within (the wrong group at the wrong time in the wrong system with the wrong campaign)
Call of Cthulhu: Tatters of the King (early TPK)
D&D 4e: H1-E3 Orcus Campaign (even just running "highlights" it was too slow)
D&D 5e: Princes of the Apocalypse (I later did the campaign with another group, but the first time it fell apart because I broke up with my gf and I was running this with her family)