I don't share your pessimism, and that's mostly because I've followed a lot more of the research into why US infrastructure costs are unreasonably high. To put it simply, excessive costs tends to come from a combination of overdesign (in particular the need to add lots of goodies to buy off stakeholders who can otherwise arrest the project), extra overhead in design costs, extra overhead in the way contracts are let, and incompetent management of contractors. But this is the sort of project that doesn't have the design stages to let that scope creep come in--it is pretty much "order off-the-shelf part number 42341 instead of 23421, then do routine maintenance tasks to replace old parts with new ones".