You know what really highlights Americas decline for me? The lack of grand infrastructure projects over the last 50+ years. 

I don’t think we could build the Hoover dam today or the Golden Gate Bridge. It would take 30 years and go 900% over budget. 

When you look at empires that have fallen through history, many of them built their most grand structures early in their reign. The great pyramid, the colosseum, the temples of Angkor wat, were all built early in the reign of their respective empires.

I don’t think that’s just the USA, I think it’s partly to do with the bidding model used to get the contracts. They take the lowest one and are somehow surprised when it goes over budget… but the contractor got the the contract so they don’t care they just overspend.
In the UK we had the HS2 project, meant to be London to Manchester high speed railway. Although needed it was some what of a conservative vanity project. They bought, forcibly the land, destroyed tons of woods etc, went horrendously over budget and has now been scrapped except for a tiny part that goes no where!!