This just isn't true at all.
Average state schools that are affordable to the vast majority of students through income based student loan repayments are far better than mediocre.
The US has 1/3 of the top 500 ranked colleges in the world, and nearly 1/4 of the top 5000.
http://www.webometrics.info/en/node/54
There's a reason that international students flock to even low ranked state schools in the US.
I wouldn't say that is filling up.
- The USA is massive compared to every first-world nation (in the West) in terms of size / population / schools. I'd be shocked if a place like Sweden were somehow the top, statistically.
- I know a few people who came from India to study here because it put them on a fast track for a visa (or whatever they're using to work here after graduating). So they based it on post-grad opportunities, not the education itself.
But assuming you can't get into those schools, any middle ranked US state school is a better bet.
I wouldn't say that for college level education. Why is then the US the top study abroad destination in the world?