The use of systems engineering tools and methodologies for applications outside of the traditional engineered system domains is on the rise. In particular, systems engineering is seeing increased popularity in urban planning (commonly tied to the concept of the smart city), healthcare, and sustainable development. Many researchers and practitioners may be unaware of a previous boom in the popularity of such applications that occurred in the United States during the 1960s and 1970s. At the time, numerous unexpected challenges were encountered, leading to high profile failures and backlash from urban planners, politicians, and the public. This paper seeks to review that history, identify specific pitfalls, consider which ones are still relevant today, issue recommendations for how current practitioners may avoid them, and identify how ongoing research may help obviate the remaining pitfalls.