The US and Europe went trough a very bad recession between 2007(ish) - 2010 (ish). Thousands of people lost their jobs, their homes, companies went bankrupt, it was really bad. Even though the worst has passed, the economy has not fully recovered (I'm talking about the US now), we are almost there. The good news is, employments are up from last year and, according to CNN Money, 2014 has been the best year for job growth since 1999, only the month of November has seen over 300 thousand new jobs, amazing since a considered "strong" month would be 200 thousand.
During the recession many expats left the US and went back to their countries. I know a lot of Brazilians that used to work in the US went back home, the same thing happened in the UK, a lot of the Polish people who lived and worked in various parts of the UK went back to Poland.
I guess now that the unemployment rate is decreasing and the economy is improving we will see more immigrants entering the US and Europe again, that's a guess, as I am not an economist ;-)
Even if you don't live in your native country you should always understand how your new country's economy is doing, so you can make better decisions for you and your family.