Be careful what you say about Nick Drake: certain of his more zealous fans tend to get a bit scritchy at the merest suggestion of imperfection. I guess that's the way of it with most legendary, little-understood, introspective singer-songwriters.
His name lives on stronger now than ever in his lifetime — especially after one of his songs, Northern Sky was featured on a soundtrack album of love songs from a dull but otherwise harmless television series called Heartbeat.
The real reason for the endurance of his music, and the gradual cultivation of the myth of Nick Drake, though, is that there is precious little of his material available. His recorded and released output consisted of just three albums: Five Leaves Left, referring to something Rizla cigarette paper users will be familiar with; Bryter Layter, presumably during the period of bad spelling; and Pink Moon, for which I have no explanation.
Since his death, Time of No Reply was added to the musical canon, and features his last studio recordings. And that's the sum total of it, unless you are lucky enough to have got hold of a copy of the home recordings, made at his parents' home in Tamworth-in-Arden and now occasionally available on CD, but more typically as an nth generation copy on cassette (where n is a large integer, and the quality of the recording inversely proportional to n), or were brave enough to buy Brittle Days, a tribute album, which in the true spirit of tribute albums does the original songs little justice.