I mean, the US are not even 250 years old and built by immigrants. The rest of the world didn't wait for them for science, medicine, art and philosophy. From a social standpoint they're still 20-30 years behind most EU countries for example.

I think most americans fail to recognise how much propaganda they're constantly fed about how great the US are. From the outside it almost looks like a parody, especially since Trump is in the office. Example: https://www.vox.com/2014/6/16/5814270/the-successful-70-year...