The explanation is that the American dollar is overvalued and has been since Nixon took us off the last vestige of the gold standard. The result has been to make foreign goods cheaper here and American goods too expensive to compete.
Taxes, union benefits and onerous regulations certainly contribute, but its the Federal Reserve's monetary policy (with, of course, the willing complicity of presidents and the congress) that has hollowed out our manufacturing.
This is why Bernanke and Obama have embarked on a desperate ploy to lower the value of the dollar. They're going about it in the wrong way -- printing new ones to make the old ones worthless.
The correct method would be to stop inflating and to stop playing with interest rates. A stable dollar and interest rates that reflected the true scarcity of capital would gradually allow us to discover our real comparative advantage and to stop jumping through the financiers' hoops.
It isn't destiny that we "progress" into a service economy -- look at Germany. We have only ourselves to blame for having allowed Washington to fiddle with our money according to the latest academic fad.
Are you talking about actual manufacturing in terms of units or tons, are you talking about value added by manufacturing, or are you talking about direct employment in manufacturing?
Lots of ways to evaluate it and describe it, but if you want to demonstrate it to us you'll have to also compare our domestic manufacturing against world manufacturing in reference to the same factors.
We all know we've had massive industrial productivity gains over the last 20 years ~ and that has hurt employment, but not units or tons shipped, or value added.
The real problem isn't employment levels, it's UNEMPLOYMENT levels ~ mechanization, automation, computerization and robotics guarantee the number of unemployed people is going to skyrocket. and that doesn't have a darned thing to do with what the funny little foreign guys are up to.