Automated manufacturing is vastly more reliable and higher-quality than anything manual labor can pull off. As the standard of living rises in China and cost of labor exceeds the threshold, automation will take over just like it has here.
The death of US manufacturing is a little overblown (though not entirely) - what people are really talking about when they bemoan the death of American manufacturing is the death of American manufacturing jobs.
Exactly, if you look at manufacturing output, America has remained a leader [1], but the number of people employed by manufacturers has gone down. The recession did put a dent in that increase of course.
[1] http://investing.curiouscatblog.net/2010/02/17/usa-china-and...
The long work weeks continue because apparently we are willing to trade less time at work for more stuff. If you want to live a 1960s lifestyle with a 60s size house, 60s level health care, 1 car per family, only 60s era gadgets, and cooking the vast majority of your meals--you could easily do it on 20 hours a week for most jobs.
As an experiment to illustrate my point, look around the room you're in and count the things that you own that didn't exist in 1960.
The same applies for anything from textiles (we can now buy clothing for a few dollars that would once have only been available to royalty) to electronics (in a world where almost everybody carries a mobile phone).
There's no reason to assume that this time it will be different.