There is a semi-famous quote by a science fiction writer that basically asserts that peace, prosperity, industry and maybe democracy are a fluke in history and poverty and violence is pretty much the norm. There is also a reference that humans won't really appreciate the former when it's occurring. What's the quote and who said it?
Was indeed Heinlein (Goodreads link):
Throughout history, poverty is the normal condition of man. Advances which permit this norm to be exceeded—here and there, now and then—are the work of an extremely small minority, frequently despised, often condemned, and almost always opposed by all right-thinking people. Whenever this tiny minority is kept from creating, or (as sometimes happens) is driven out of a society, the people then slip back into abject poverty.
This is known as "bad luck.”