Yes, if companies didn't outsource it would greatly help the economy. A huge huge huge amount. Think of all the jobs it would create in the country. Money going to US citizens, that money then getting spent by US citizens inside the US in shops etc.
But companies companies are global entities and they care little for the economy of any 1 nation. Massive companies have their own economy they're so big. They're almost like countries themselves and so they only want to benefit their own 'country'.
They're in essence a sort of country dealing with other countries. mini-economies in the mix of world economies. The only difference between a major company and a country is the company has to base its self within the sovereignty of another nation and operate within their laws. But in terms of economics you can think of these big companies as countries with their own economy.
But when one thinks of finance on a global scale, global debt it's all about control. Debt is an illusion. There's only so much wealth available on earth. Debt is just an intricate web of wealth ownership which allows the few to control the many. Basically debt is control of people.
What does money buy you? People. I could hire someone here to write me an article, to design a web page, to do some seo. I'm paying for a slice of your time. If you're in debt to me, then your physical time is in debt to me.
Time = money
Money = time
To get money you have to spend time. Money also gets you the time of others.
So the world banks that control the money, control the time, thus control humanity.
The whole system is all just a giant farce that benefits the few but you can learn to game it and take a slice of that pie for yourself which is what we all do on this forum.