TCR could have been justified by everyone having massive faith in the future, as OP is suggesting happened with roads. But you're quite wrong that "few people sat around asking whether or not it was worth it", as Iron Empires details:

https://www.amazon.com/Iron-Empires-Robber-Railroads-America...

it was hugely controversial in Congress.

I don't happen to know about roads, since that wasn't one single thing. But I doubt they happened because of blind faith in the future, either -- it was probably more businesses demanding roads NOW. So the argument that no one questioned them is dubious at best.