Do you think most actors are one trick pony's?

i couldn't find the right words to ask the question in the headline so ill try to make my point clear here. almost every actor i have seen seems like they are playing the same character. even the great ones like jack nichalson, robert duvall, Robert dinero. i see some variation with some actors like Al pacino like scent of a women from the godfather series. im not saying its bad. i could watch these guys play the same character in a hundred movies and not get tired. Actually the one actor ive seen that would make me go "is that the same guy," is Heath ledger. i mean he played the Joker, cowboy, knights and they all had different tones and quality you would think they were played by different people. i could be missing an actor whos like this, but overall, do you think most actors play the same character?