I know what state America is in - I've written articles about it. Don't bother reading them, I'm only a White person so my thoughts don't count to you, do they?
From Africa to the Middle East to China the civilisations have done exactly what Europeans did. Conquer, colonise and exploit their neighbours - or did you forget about the Mongol Empire, the Mthethwa Empire and the assorted Caliphates of the Middle East? People are people and they'll all do the same damn fool things given the opportunity. European and British damn fools just did it later and better than anyone else because of advanced technology. The Industrial Revolution was an enabling factor in British imperialism, not a result of it. Nor did we get that much out of it. The life of a Black labourer in a Jamaican sugar plantation or a Hindu worker in a tea plantation was no harder than that of a Yorkshire miner, a Lancashire cotton-mill worker or a London docker. 'Free' doesn't mean shit when you don't know where your next meal's coming from.
If you want to go back to the ways we all used to live, you're welcome. Enjoy the thirty-year average lifespan and the 75% infant mortality rate. Because that's how it was everywhere (including the US, Britain and Europe) until the 1940s at the earliest. Hope it works out for you.
We were fine without Black people. It's only America who needed them so much.
We were also better off without an Empire than with one. Only the capitalists benefited from it, and they are, by definition, scum.