This shows a complete lack of understanding of economics on your part. If the factories were still here then the factory workers would also be consumers, they would use services and this multiplier effect creates even more jobs. They would also pay taxes and the local small town goes on. THIS HOW AN INDUSTRIAL ECONOMY WORKS.
1. Could U.S. consumers even buy every air conditioner that the industry has the capacity to produce in a U.S. plant?
2. If I have a choice between buying an American-made air conditioner for $300 and a foreign-made one for $250, I'll buy the American-made one. But that means there's $50 less for me to spend on something else, doesn't it?
I'm sure the U.S. shoe industry doesn't rely on any "multiplier effect" from me ... because I just bought my first new pair of shoes in about seven years.
I'm sure the U.S. auto industry doesn't rely on any "multiplier effect" from me ... because I'm driving a truck that is more than 10 years old.
And I really hope that my $300 air conditioner lasts me 15-20 years ... because if it's just going to crap out after five years through a "designed obsolescence" strategy by the manufacturer to keep me coming back to buy more, then I might as well buy the foreign-made $250 model.
The "multiplier effect" you describe isn't the only thing involved here. In an industrial economy, there is an insatiable need for an ever-growing pile of new consumers to keep the industrial base functioning ... which is what drives our open-borders immigration policy. Are you an open-borders advocate now?