The Irishman begins with Robert De Niro’s veteran mafia hitman rambling from a wheelchair in an old people’s home – the last, befuddled survivor of a forgotten era. It would be so easy to view Martin Scorsese in a similar light. First there were his cranky-old-man comments about not considering Marvel movies to be “cinema”. Now comes The Irishman itself, which on superficial inspection looks like a three-and-a-half-hour wallow in the 76-year-old film-maker’s comfort zone, and doesn’t come close to passing the Bechdel Test.

If Scorsese was on Mastermind, his specialist subject would surely be “male Italian-American criminality of the late 20th century”. In theme and cast (De Niro, Pesci, Pacino, Keitel), The Irishman is of a piece with previous Scorsese works, from Mean Streets to Goodfellas to Casino – although the ages of the performers does add an elegiac note to proceedings this time.

But here’s the thing: Scorsese is still one of the most radical film-makers out there. He is the old dog who’s constantly learning new tricks. Take The Irishman’s bladder-challenging running time. You could read it as another case of auteur self-indulgence, and question whether it might have been better as a miniseries (Scorsese was an early defector to the small screen, directing HBO’s Boardwalk Empire). Alternatively, you could see The Irishman as a bold experiment in stretching the conventional crime thriller into something new and interesting. In a recent interview with Sight & Sound, Scorsese talks about “trying to tell stories in a different way”, going less by plot than “intuitive connections”, in an almost improvisatory manner. He succeeds brilliantly. It is expansive and richly detailed but solidly structured, filled with scenes that become all the more riveting for their length. The movie also pushes the envelope of CGI with its “youthification” technology. New tricks.

No Hollywood studio would have made The Irishman. Ironically, what allowed Scorsese to pull it off was Netflix (much like his recent Bob Dylan film, Rolling Thunder Revue). Streaming services are often cast as “destroyers of cinema”, but Scorsese is using them to save it.

What unites his anti-Marvel comments, The Irishman’s scale, and much of his career, is Scorsese’s commitment to film: making it, moving it on, helping younger directors make it (recent producer credits include Joanna Hogg’s The Souvenir and the Safdie Brothers’ Uncut Gems), preserving and restoring it (as founder and chairman of the Film Foundation), and sharing his love of it (he has made documentaries on American and Italian cinema, with a British one reportedly on the way). Rather than sitting in his wheelchair waving his stick at the screen, Scorsese is still fighting. He is the best defender the medium has ever had.