What's wrong with america?

I know that the US now faces a lot of problems (like debt, deficits and immigration) but I lately I feel that our biggest problem is our "spirit". I mean we used to have this ambition, or imagination, you may say, to build BIG like the golden gate bridge, Hoover Dam and other similar projects, but now, think about it, when was the last time we built something or made something like we used to do 50 years ago ? Even high speed rail now faces opposition !!! What the hell is happening ?