IMO people consistently underestimate how much public infrastructure is worth. The US highway system was sold at a cost of $27B [1] but cost over $100B and has cost nearly $500B today [2].
Does that mean the US Highway system wasn't worth it? Of course it was, the public just doesn't understand how much it had to cost. The Iraq war cost trillions for zero benefit for future generations, even if 50% of the cost of HSR is waste it's still a better deal by far.
[1]https://en.wikipedia.org/wiki/Federal_Aid_Highway_Act_of_195...