Although The Monkees' Head
is not technically an SF/fantasy film, it's surreal enough that I think it's fair game to discuss here. It's certainly an interesting film, experimental and bizarre. I can see why it failed at the box office; it defied conventions of narrative logic so it wouldn't appeal to everyday moviegoers, yet it was such a deconstruction of and protest against the Monkees' prepackaged media image that it's no wonder the fans didn't go for it. (Imagine one of today's manufactured, autotuned Disney pop idols trying to do something like this.)
Yet it's interesting how it comments on that prepackaged nature. The Monkees admit in the second song that, yes, they're manufactured, they're not a "real" band. And yet later we get Peter channeling the Guru's wisdom that the mind doesn't distinguish between reality and a persuasive illusion -- and the whole stream-of-consciousness structure of the movie is about challenging our perceptions about what's real and what's illusion, and ultimately dismissing the distinction as irrelevant. (And having Peter, whose traditional role as "the dummy" was emphasized earlier in the film, break character and deliver the core insight further deconstructs the illusion.) The experience is what matters, not the underlying cause. So what does it matter whether the Monkees were created for television or not, so long as their music reaches people? And I daresay that in the long run, the Monkees proved that point, though it took a few decades.