To the OP, you're looking for something like this?
An Origin8 22.2 quill / 25.4 bar clamp stem on Amazon for like $20
There's plenty of others there. Or if you needed a traditional-looking road stem in those measurements, look at Jenson USA for example. Sometimes people run out of specific things, and there are certainly less bikes these days using an internal 7/8" quill stem and a 1" handlebar.

As far a return to American manufacturing of mainstream bicycles, others have opined on why it's unlikely for a new company to spring up... I'll just add re: the idea of a formerly-made-in-USA bike co. bringing production back to the US that it's just as unlikely as it would be for WalMart to start selling US-made stuff instead of the cheaper, readily-available Chinese-made equivalents.
US companies started outsourcing production etc because it was cheaper to do so, and that enabled them to do 2 things:
1.make more profit (and pocket that) from producing the same stuff as before / start producing lower quality stuff and
2. pay their workers less in total compensation (stagnated pay, and/or reduced benefits like pensions, healthcare plans with good choices, or coverage for retirees, etc)

It's a difficult thing to reverse!