Quote from ByLoSellHi:
I'm not being sarcastic or coy, but a short response can dispatch of the above sentiment quickly:
History is replete with once wealthy nations that made that critical turn where "the children no longer lived better than their parents."
The roadside of history is replete with the skeletal remains of once wealthy empires.
Britain & Spain are two examples. Both have lower living standards, by far, now, than they did in generations past.
Small but vital point: we're not an empire.
With the exception of the War of 1898, we never went in for imperial acquisition, and the largest country we got a hold of in that war, the Phillipines, long ago became independent.
The expense of having an empire is a large part of what did these countries in. We don't have that expense. More than that, we don't have the drain on our youth that having an empire takes from you. Our youth can continue to make us richer by making their new ideas reality; they're not dreaming of being the Viceroy of India instead. (Although, arguably, shipping off windbags like Curzon to the colonies was probably a net gain for the British. Oh well.)