I'm confused by that as well. Europeans came over from Europe to find tribes populating the New World. They were mistakenly dubbed "Indians" because they thought they had landed in India. They were wrong. The New World was populated by many different tribes and "nations." They were, and are lumped into one big category as "Indians." That term was inaccurate. Native Americans seem to describe them as a whole better, Though the Americas was a term that Europe used for the New World, I believe.
To be precise, you would have to say the Cherokee, Quapaw, Navajo, Aztecs, etc. etc. etc. There were hundreds of them. We dubbed then "Native Americans" as they lived here prior to the Europeans.
The only reason the US is here today is because the Europeans had guns and the Indians did not. And because the Europeans were larger in number. After the Revolution, the US systematically expanded westward, and where that clashed with the Indian tribes, they systematically slaughtered them, and then forcibly made them agree to live on a "reservation." The history is quite terrible when you read about it. It is what it is today, but one cannot deny that the US committed a terrible sin against them. Some will try to argue the Indians were salvages, but they were often times merely trying to defend their hunting territory and homes. They did not see land as something that could be individually owned, as Europeans and later Americans did. They saw it as a common resource to be used. Some tribes followed the buffalo, having a symbiotic relationship with them, and managed very well. Others migrated with the weather.
At any rate, there is no undoing history, but terrible things happened in the US past. This was done in the name of "Manifest Destiny" and the belief that God desired the US to occupy the entire continent from Atlantic to Pacific. And it was accomplished, often crushing the native American tribes that dared get in the way or try to defend their hunting grounds.
And slavery and segregation and systematically oppressing groups of people were terrible sins of our nation, for which we are still paying the price today through high poverty rates among African-Americans.
All that to say, to say the US was better in past years, to me, seems to ignore history. I do not dispute that there are some great challenges today. But we also have great things happening today. Our challenges today are merely different than they were in the past. Our sins today look different, but are still there. The good things occurring are there as well. Our generation or time in which we live is not unique, it merely looks different and the challenges are different. The underlying problem, being a battle of good vs. evil, remains the same.