Indeed, look at what Franklin Roosevelt was able to accomplish in his four terms as US President. We almost had nationalized health care system. Continuity of executive leadership has tremendous impact on a country’s ability to function and grow.
I think one thing is who is the president. Another is the massive bureaucracy that sits below them and does all this detailed policy formulation. It is the latter, and their ability to plan in a both realistic and strategic manner, that really makes the difference.