Francis Ford Coppola had a run in the 1970s that few directors match: The Godfather, The Conversation, The Godfather Part II and Apocalypse Now in seven years, with two Best Picture wins inside it. He then spent the following decades funding personal projects with commercial work and periodically risking everything on them.
Apocalypse Now nearly destroyed him. The shoot ran over a year, a typhoon flattened the sets, Martin Sheen had a heart attack and Coppola mortgaged his property to finish. The result is one of the few American films that genuinely feels unstable, and the reason is that it was.
He has repeatedly bet his own money on films the studios would not make, most recently Megalopolis, which he self-financed by selling part of his winery. The pattern is consistent across fifty years: he treats filmmaking as something worth going broke for.