I don’t live or work at the US, so I don’t think my opinion is worth more than shit. But I would guess you are mixing private with public projects. Private projects usually go on schedule because they’re not a lot of parties involved and everyone wants to finish the project asap to start a new a one. With public ones you have a lot of people involved because everyone and their granma think their opinion is valid and they are being affected. But this is the same on basically everywhere on the world, except maybe China.