Singapore and Dubai don't even have functioning democracies. I doubt that many forumers who read this thread would want the US to emulate their political systems!
Iceland and Canada are great, but too cold for me. Remember that the population of Canada is only 37M while US is 330M. California alone has more people than the whole of Canada. Iceland is just 357,000 people, a suburb of a big city. You can find many suburbs in the US that are so much better than Iceland! And yes, you can be poor and alone in Iceland, too. Plus the cold.
Australia, NZ, Austria are also great. Australia has population of only 25M, New Zealand 5M, Austria 9M.
Remember, Trump is the worst president ever. And yet, there is no great immigration surge from USA to Canada. Remember the news headlines before the 2016 elections? Everyone and his dog would immigrate to Canada if Trump was elected.
So, my conclusion is that USA is still #1 in the world. If it isn't, then please tell me which country you think is #1 in the world today.
(Well, California would be the #1 if it was a country, but currently it's a part of the USA. California exceptionalism rules!
And no, I wouldn't want to live in Alabama... )