even if one were to reduce labor costs to china level, china has the infrastructure (technological and industrial) to build things and the countries that were abandoned 20 years ago do not, not anymore and not at the level they have.
it is not about, say, producing mobile phones or cars, it's about the steel and plastic they need. and at least all around my area all refineries and mills are long gone. even if we drive down labor prices, china is now technically more advanced than us and at a scale we would never reach.
However, latest labour force survey indicated that ~ 1.7 million people still work in manufacturing. While this is the lowest number of manufacturing jobs in Canada since 1976, it still employees a relatively large percentage of our work force. The issue that worries economists is that a large percentage of our remaining manufacturers operate below capacity. When our dollar declined relative to the U.S. dollar, some economists thought it would slow the slide, but the issue remains that manufacturing still costs too many Canadian dollars. Since NAFTA prevents our government from directly subsidizing manufacturing (in most sectors), lowering labour cost is the best tonic left.