Because if you succeed, it reinforces the fact that they are not where they want to be. They know instinctively that there are only two ways to make their building the highest structure in town: build an even bigger one, or tear down all the others. Since the odds are against them building the big one, and since it takes just too darn long to start seeing any results, and since they are not at all aware of the slight edge, they’re going to take the path of least resistance and go into the demolition business.
