Some films have cult status due to time, geography, or message. For example, I feel that Buster Keaton's The General (1926) is unknown and yet one of the best films I've ever seen. Like the other comedic films I've seen, I expected Keaton's physical comedy to be exaggerated beyond belief... but his movements are so subtle and understated that I found myself riveted. You've seen Danny Kaye in The Court Jester, Jackie Chan in The Drunken Master, and Jim Carrey in The Mask.... and those performances are hilarious and the physical comedy demanded everything from the actors, but Buster Keaton goes to the other extreme and is brilliant.
As for geography, Bajrangi Bhaijaan (2015) was a major hit in India (nominated for Best Film, Best Director, Best Actor) and yet is probably unknown in the U.S. The plot is about saving a little girl, personal redemption, and international brotherhood with songs... well, imagine Ron Howard directing Forrest Gump as Jean Valjean... and that's basically it. It pulls at your heartstrings incessantly... It's about forty minutes (159 min) longer than it needs to be (for me).
Courageous (2011) is a no hold barred challenge to men. It's made by the Kendrick brothers, so that means a Christian message... and much less of a budget than a Marvel Avengers movie. The film opens with Nathan's courageous car chase with a surprise ending... it moves on to Adam's hilarious confrontation with Javier about his the terms of his employment... and deals with Adam and his family's heartbreak.
In the right demographics, all three of these films are popular.