Taxi Driver didn't really find a buyer. The script wasn't actually sold in that way. I was reviewing something that Brian De Palma had done. It turned out he was a chess
player, so we were playing chess, and I told him I had written the script. He read it and liked it. In fact, he wanted to do it at that time. He gave it to the producers Michael and Julia Phillips. They wanted to do it. And then Julia and I saw an early version of Mean Streets, and we really felt that Marty Scorsese and Bobby De Niro should do Taxi Driver. Marty wanted to do it, so we made an arrangement with Brian, and then we had the group of us together—Michael and Julia, De Niro and myself, and Scorsese—and, of course, we could not get it made.
But we all had a blast of good luck. I sold The Yakuza. Michael and Julia won the Oscar for The Sting. Bobby won the Oscar for Godfather II. And Marty had a success with Alice Doesn't Live Here Anymore. Suddenly this group of people who couldn't get it financed did get it financed, albeit as a kind of charity job from David Begelman at Columbia. It would not have been financed today. It was a studio system where they would occasionally make a film like this just to keep a diversified slate.
Paul Schrader, as quoted in Tales from the Script: 50 Hollywood Screenwriters Share Their Stories