The reason for rushing government construction is that the way contracts are written construction delays almost always cost the government exorbitant claims in additional payments to the contractor. The contractors get administrative costs, lost profits, rental costs of idle equipment that they themselves own, etc. It’s a windfall for them.
I’ve seen it happen time and time again. The contractors’ lobbies and their lawyers are among the best in the country. And they have Congress and State legislatures in their pockets. The laws are written in their favor to prevent them from losing money.
The free market runs on self interest through voluntary cooperation and creates wealth. Government programs, initially labelled with a "public good" goal, actually runs on its own self interest through coercion and creates misery and poverty.