What critical mass? What exactly is the problem on the scale you allege?
Unemployment is so low that it was not even considered to be possible until a few years ago. What critical mass?
The method of how unemployment and inflation is tabulated was changed in the Clinton admin, the real unemployment rate being closer to the U-6 numbers the BLS comes out with every month compared to the U-3 numbers. Also the offical number does not take into account underemployment. You have to go beyond the offical numbers and see what is the basis for them and the reality.
The reality is median wages have stagnated, things people need to survive, such as housing, medical, energy and food prices have gone up, hence why consumer confidence numbers have not gone up with the recent reprots on GDP. While the economy has been kept afloat by a record amount of govrenmnet spending and a real estate bubble that has allowed people to use their homes at ATMs, neither of these trends can last forever.
I am 100% convinced that if neither immigration and job outsourcing issues are adressed, the political landscape will change dramatically.