The United States is ahead of the rest of them by a huge margin, and unfortunately this gap is increasing with every passing year.
I agree with most of your statement except this one. Their roster this year is not that far ahead of Serbia. If they ever lock horns later in the competition, I think Serbia will win.
If you also gamble in this competition, you might win bigger with the good odds of serbia, they are the 2nd best team based on the ranking from the betting odds so that makes them a tough competitor for the USA.
Serbia is Serbia +350, meaning if you bet 1000 usd for serbia, you will get 2500 as your winning, that's a good odds right?