The problem with infrastructure spending isn't that it doesn't potentially have a good ROI, it is that the process channels the money to wasteful projects that don't have a good ROI.
This is what happens in every ecosystem as the available energy sources become fully exploited. Featherbedding and cronyism are the parasitic vines which strangle enough trees so that when the next lightning strike comes the conflagration is inevitable. They cannot exist without the forest. When the forest grows to maturity they become inevitable.