Democracy is a nice ideal, but hard to achieve in reality.
Since full consensus is impossible in reality, the rule of a simple majority is but a symbolic token of the high ideal of democracy.
Even so, a fair simple majority is so hard to get. Zimbabwe today is a case in point, where so much human suffering is engineered just for one man to dominate the politics. Examples abound in other countries.
Domination comes when a man stays too long, and has the time to control the system.
That is wisdom in limiting the top positions to one term or two terms.
We only have to suffer their greatness or incompetence for a short time; the great ones so that they do not become arrogant and destroy the society, and the bad ones so that they stink and destroy the whole society.
Don't trust people, build a good system.
How about the argument that in a small society, there are not enough talents to go round. My answer is: when there is opportunity, talents will come forward.
The term may be too short for the leader to accomplish anything. That's the idea: Not to give the person time to do anything. The people should have the opportunity to do something for themselves; and the system should do the work.