If he'd died at 27, Layla would be his last album. Really though, that would help his legacy with certain music geeks, but he would be less well remembered without the later 70s and 80s hits, even if people would still remember him for Cream and Layla.
Layla is a plausible cutoff. If he hadn't kicked his heroin habit then that probably would have been his last album. I think Pete Townsend urged him to go to rehab and helped organize the Rainbow Concert to raise money for it. Otherwise he probably wouldn't have lived much longer. Then he stayed off of illegal drugs (I think) but started drinking, which he quit in the early 80s.
If he drunks himself to death in the early 80s then he leaves the albums this comp is take from:
https://en.wikipedia.org/wiki/Timepieces:_The_Best_of_Eric_Clapton
and one more album with I Can't Stand It on it, but not 80s hits like Forever Man, It's in the Way That You Use it, Bad Love, Old Love, and Pretending. Also no Tears in Heaven/Unplugged and his popular traditional blues album From the Cradle in the 90s. I dunno what real part of his biography failed to kill him in between From the Cradle and Pilgrim, but after that the only real highlights are the Cream and Blind Faith reunions.