"Walter Matthau and Bruce Dern are...
...The Nice Guys."
Do you think they would've been appropriate for those roles? Matthau, of course, didn't have a naturally imposing physical presence the way Russell Crowe does, but he could've projected one, I think. His role in Charley Varrick, in particular, goes to show he could play a tough leading man when he wanted to.
And with that moustache, Ryan Gosling looks quite a bit like Dern in The Laughing Policeman.