After the end of the war, capitalism rises and our society shift from the production to consumption. Same as the creative industry, the design have been commercialise and people tents to treat it as commodity.
The template design site is selling the design like a product. Providing different of variety and tone of option to let the buy to select. For example, they can sales something small like logo, business card and flyer template, to something big like magazine template, website template and etc. Same like the McDolnalds, these design are sold cheaply, everything is ready made and can get it easily.
It also shows that the template design are meaningless. It is because a true design should consist the process of concepting, research, sketching, problem solving, evaluating and etc between the client and designer. These zero human interaction product are like the French fried or burger in the McDonalds, which is ready made and nothing is prepare by the human delicately.
Reference:
Ritzer, G. (1997) "The McDonaldizaton thesis," Sage Publications Ltd, pg. 118-113