Aside from his anti-gun activities ... which is quite an aside ....
Our patron saint John Wayne never played anything but John Wayne in any movie role he did ... for instance, he was John Wayne as Rooster Cogburn .... and I believe that, had he been writing his own script, that The Shootist is exactly how he would have preferred to end his life...
Jimmy Stewart is another actor who comes to mind. Wether in Winchester 73 or It's a Wonderful Life or the Strategic Air Command, he was simply Jimmy Stewart playing a role.
For all his limitations, and I do not minimalize them, when we watch him, he is still this small-town kid from Visalia made to deal with a situation much larger than he was ever raised to be in ... I think that is what we identify with in each actor.