It’s a classic problem solving technique to take some of the free variables in the problem space and nail them down. Holding something constant reduces the complexity of the search space. The designer may select what to pin down based on his rough estimate of the cost of manipulating that aspect of the system. For example the real estate developer may decide to treat the zoning laws as fixed, or he may decided to expend the effort to change them.
Clay has two postings this morning that illustrate examples of introducing scarcity intentionally to capture a longterm value for the system under design. This first quote is Clay’s:
When they were re-building Parliment after WWII, Winston Churchill is (said to have) said