By any other time do you mean NOW? A couple hundred million Europeans may have a different idea, as might a few dozen million Canadians. This kind of American "exceptionalism" seems like worn out idea in 2018. There are far too many Americans who quite rightly are not waking up feeling lucky today. Millions, actually.
I think we have a lot going for us here, and yes for many of us, things are as good here and now as they would be anywhere else and at any time. But statements like yours make it sound like billions of people think they'd be better off here, and that just isn't true. Would some? Of course. But those are truly the most needy and oppressed people in the world.
You sound like my very naive step-mother who honestly believes America is the only place where people are even free to vote for a candidate of their own choosing. She couldn't believe it when I listed the other countries of the world that encompassed a majority of the Earth's population where free elections were just as common as they are here (sometimes I suspect MORE common).
I like my country. I'm not looking to go anywhere else just right now. But the idea that this is the best it has ever been in the world is not only naive, I think it is damaging since it clouds our minds to the possibility that somewhere else they might do something better.