Didn't win any awards

Agree - such a superb actor. At the very least, he should have received some recognition for Shadow of a Doubt and Portrait of Jennie.

same for Edward G Robinson

I always thought of him as a stalwart, dependable kind of leading man - which is perhaps another way of saying he did all the basics well but never did anything flashy? It seems to me that actors like this are simply there for much of their career and it's only in the latter stages when they suddenly step out of character that people suddenly say - wow, this guy can act, give him an award.
Also this quote, “I didn’t care about the movies, really,” he said in his 80s. “I was tall. I had curly hair. I could talk. It was easy to do.”, perhaps indicates he didn't take it terribly seriously.

I reckon he had a good screen presence. He admitted himself that he didn't take acting seriously. So perhaps his nonchalance was his problem. I always like him in his films though.