In the blueprint that is made by a planner there cannot exist really new phenomena. Nobody can predict what knowledge will be at the disposal of future generations, but it is absolutely sure that there will be several new ideas and possibilities that didn't evolve out of former situations. When modern planners come to power they will try to force the society to fit the blueprints they have made. Everybody has to obey their prescriptions and they will work against every attempt to realize new ideas. They will 'stand with their backs to the future'.
New developments are in conflict with their models and as such dangerous and unwanted.
The result is a society that falls short of its possibilities and, above all, is unsatisfactory for its inhabitants. There is a great lack of freedom and that results inevitable in a sincere indifference of the people. There is a good example for the disastrous influence of modern planners. This goes so far that you can speak of a form of epidemic obsession. In their blueprints namely it is essential that everybody has a paid job.