培養需期太久。一來若成功完成所需培訓,同業惡性競爭的機會不大。可以說下半輩子生活有了保障,不會餓肚子了。《亞當.史密斯》在其《國富論》裡分析道:- "We trust our health to the physician, our fortune, and sometimes our life and reputation, to the lawyer and attorney. Such confidence could not safely be reposed in people of a very mean or low condition. Their reward must be such, therefore, as may give them that rank in the society which so important a trust requires. The long time and the great expense which must be laid out in their education, when combined with this circumstance, necessarily enhance still further the price of their labour."