Beginning with the plays debut and continuing to today's performances, the set and props of our town have been minimal. What is the main reason for this approach to staging?

The main reason for this approach to staging is: It lets the play be performed outdoor

By having minimum props, the play could be played even in the middle of the street. On top of that, they play intended for the audience to focus their attention to the interaction between the characters. Fancy props will only divert their attention to somewhere else.