Perceived presidential power

A thought popped into my head today regarding this weird overestimation Americans have (or at least the American popular press has) of the President's ability to get shit done: Perhaps it is easier for people to praise or blame a single person rather than a group (Congress). If the executive branch were headed by a triumvirate, would there be less of a laser-like focus on its importance?

I'm not much of a political scholar, so I'd like to know if this idea has any relation to reality.