> Did the US lose control of the most populous part of its “empire” in the last 20 years?

I might count alienating NATO and China's growing independence as uncomfortably close to that, yes.

> Has the US just come off of required rationing for basic food stuffs and been running in 20 years of austerity?

Doesn't that make our inability to effectively project power more embarassing? We don't even have to scrap our warships to fund operations; we're dismantling our global soft power sources willingly.

> Or is the US still the dominant economy in the world, with a problem of over abundance of staples and stuff?

Like the UK once was?

By the time of the Suez incident the uk hadn’t been the dominant global economy for going on 70 years. The second Boer war is probably a better example of shocking poor outcome for their empire by that timeline.

Queen Victoria was still alive at that point and ww1 was in the future. Even after ww1 when it was obvious the empire was severely diminished the English retained outsized soft power at least and had until the 60s for the empire to be truly dismantled.