Magic Man
Reaper of Conversation
From Dictionary.com:
The earliest meanings of unique when it entered English around the beginning of the 17th century were single, sole and having no equal. By the mid-19th century unique had developed a wider meaning, not typical, unusual, and it is in this wider sense that it is compared: The foliage on the late-blooming plants is more unique than that on the earlier varieties. The comparison of so-called absolutes in senses that are not absolute is standard in all varieties of speech and writing.
Regardless, it still means that the U.S. would be one of very few places that offered what you said was unique to it. By using "unique", you do imply that there are only a handful of other places that offer the same opportunities as the U.S., which is untrue. If you had said it was unique outside of North America and Europe, that would have been somewhat accurate.
I'll just say this: The US is a nation built by immigrants who came here for the opportunity to improve their lives drastically. Four hundred years later and they're still coming. Our percentage of foreign born people is about 11 percent of our population (compared to 4% in the UK, 1.3 % in Japan, and - while we're at it, 1.8 % in Finland). Currently the USA is ranked 6th in the world in percentage of foreign born persons per capita.
Foreign population by country. Definition, graph and map.
So, considering there are 203 sovereign states in the world, and out of those 203 countries/sovereign states, the US ranks 6th in immigration rates, and since people generally immigrate to improve their lives, I would say that would strongly imply that the US offers many unique opportunities to do so.
That still means there are 5 states with higher percentages than us. So, are those five states then better for building the life you want?
All I would say this strongly implies is that people have an idealized version of America in their heads. "there are no cats in America, and the streets are paved with cheese." Of course it helps that we're such a huge country land-wise, which helps us take in more people than much smaller Eurpean countries.
Believe me, we're not running commercials in foreign countries enticing people to move here. They must have heard SOMEWHERE that the USA is a pretty great place to live. And since they tend to stay here once they get here, and then bring their families here as well, it must be working for them.
That's a very interesting argument, but as I said above, it leaves out the fact that there are five other countries with more immigrants than us. By your logic, that means there are five other countries with better opportunities for building your own life than America.