Type Casting

I wonder if making "Breakback Mountain" affected Heath Ledger in some way. Maybe he was the kind of actor who empathised with the character he'd be playing so thoroughly that, in a way, he would become that person and find it difficult to shake off the traits of the character afterwards in the real world. Maybe this troubled him.
Just a thought.
But certain roles do get under the skins of some actors. I feel, for example, that Anthony Perkins after "Psycho" seemed unable satisfactorilly to play any other character than the young man with the murdered mother in the window. It type-cast him.
Like Peter Lorre's performance in "M" ensured he would for ever be that lonely, murderous, crazed figure. Even in his performances as Mister Motto he seemed always to be on the edge of tipping over into psyopathic mania.
Alastair Sim was forever Alastair Sim; he couldn't be anyone else. Even as Scrooge he made Scrooge into Alastair Sim not Alastaire Sim into Scrooge.
There are few film actors who can escape the style/character their early work has created. Why should they? Aren't they successful doing just that?
Yet I feel many actors they would like to spread their wings and "do something great and different". Few succeed in doing anything different though some do achieve something great sometimes. Bogart did in "The Matese Falon", "The Treasure of Sierra Madre" and "Casablanca". But he was always Bogart.
Laurence Olivier was never type-casted. Probably this was because he liked to insinuate himself into roles where he would imitate people who were like the people he played. He was a great stage actor but never a great film actor.
A friend of mine met him. My friend was a designer with Royal Doulton; they had made a toby jug (if memory doesn't fail me) of Olivier as Richard the Third. The Company wanted to know if Olivier approved of the bust. They shook hands and sat down and my friend was conscious for a while of being studied as they chatted informally. What Olivier was doing, I was told later by someone who knew him, was trying to understand what sort of person it was he was meeting so that he could respond appropriately - in other words he wanted to present to this other person the persona of which they would most approve.
Dustin Hoffman was always Dustin Hoffman and when he played in the film "Marathon Man" with Olivier he felt he ought to become a marathon runner and set out to do this; it looked rather hard going to Olivier who one day said to him "Why don't you try acting?"