Here is the late Brian Dennehy talking about Sylvester Stallone in a lost clip just uploaded to YouTube. Dennehy, who of course starred alongside Stallone in First Blood, says that Stallone had to make his own way because he did not receive the help that other actors did.
Nobody ever gave Sylvester Stallone anything. Nobody ever did anything for Sylvester Stallone. No agent took him, no manager, no movie director said ‘this guy…!’, you know, as they did with a lot of other stars. It was always somebody else. Sylvester Stallone made himself, from the ground up. He wrote his own scripts, he wrote the part that he became a star in, ‘Rocky’. He created his own self, from the ground up. People have a tendency to forget that.
Of course, for both Rocky and Rambo the studios wanted anyone but Stallone to appear in the title roles. In Stallone’s book, he also shares some interesting stories about his early acting career, almost being destitute and receiving obnoxious abuse from producers.