There is proof that infastructure improvements grow economies, which is usually paid for through taxes. Of course there is no guarentee tax increases will go towards infastructure.
The only problem with modern infrastructure projects is that the infrastructure doesn't actually get built. They have become welfare programs in disguise.
In the past the government would choose a competent industrialist to lead the construction such as Kaiser to build the Hoover Dam. Imagine the impossibility of appointing a billionaire industrialist to build CA high-speed rail in this age.
