Yes, GDP is a very imperfect measure, but look at this graph showing GDP (as a proxy for production) over the last two millennia:
You should read this in the context of the graph below showing how the world changed for the better around two-hundred years ago—from being a flat line for most of world history, production all of a sudden shot up out of nowhere to support a rapidly growing population. What a great thing. At least this is what happened in the parts of the world where the Age of Enlightenment happened—that remarkable period in human affairs when human beings began applying reason to understand the world around them, and in the ensuing Industrial Revolution to transform it.
But as we can see above, China and India, were excluded from this happy state of affairs, at least until very recently (being a logarithmic graph the last few decades are as prominent as the first few centuries). And in Africa and the Middle East, have still yet to enjoy it.
And just ignore the big grey slug that is Russia. They were lying about their production figures long before the Bolsheviks came along.
Practice Good Theory has more thoughts.
And in case you don’t think production and wealth is such a good thing, Stephen Hicks has a neat graph showing the relationship between wealth and life expectancy. If you’re over 45 or so, you should take it seriously.