The last 200 years.
The past two centuries have seen the greatest creation of wealth in the history of mankind. This is due primarily to our realization that there was another way to become rich than going to war with our neighbors and stealing from them. We learned that through specialization, trade and allowing the pricing system as the primary source to allocate capital, we could increase wealth by lowering costs and increasing choices. This understanding may be the most significant human advancement of all time.
The debate is not whether or not markets work. The debate is whether the market works
all the time. I do not think they do, but markets are the primary driver of wealth creation and increasing standards of living. Markets do not create all the wealth for all the people all the time but they do create the most wealth for most of the people most of the time.