Newman, Redford, Bogart, McQueen and Eastwood all starred in "action" films & were all nominated at various points in their careers, but lacked the necessary tricep and ab definition that puts them in that special Stallone/Arnold category of comic book acting.
Look, the fact is that Sly & Arnold needed steroids to put themselves over in their movies. I believe that's my point.....
And Bogart and McQueen did massive loads of alcohol that may or may not have helped them with their craft. So what?
If it was just steroids that made Arnold & Sly successful movie stars, then why weren't Ferrigno and some of the other past bodybuilders who tried to make it in the movies more successful? (Talkin' to you Kevin Levrone and Bob Cicherillo.) And how come Haney, Dorian, Ronnie & Cutler aren't movie stars? They've surely done the steroids, but you don't see anyone clamoring to make them movie stars.
Neither Arnold nor Sly are Oscar caliber actors. (Yes, I know, Sly was nominated for Rocky. What other Oscar nominations for acting has he held since then? None. However, he has won tons of Razzies for worst actor of the year.) They are what they are...action stars who make believable action heroes.