Firstly, Hitler did not say that, someone just made it up.
Secondly, modern art is actually pretty old. We are talking about the period which started about a hundred and fifty years ago.
Neo classicism had its day, what is the point in trying to resurrect it? As for architecture, function is the most important element, and I'm quoting Vitruvius on that.
I don't see the point of monuments at all, and I question the purpose of all public art. Most of it is some form of propaganda, and always has been.