"Any of these vendors still make their tents (other than the custom orders) here in the US?"
Last time I talked to Judy of Lightheart Designs (over a year, maybe two years ago) she had moved her "standard" tents to being made in China --- just too many orders for her to keep up with. And I presume no credible price-for-the-quality alternatives in the U.S. But if you ordered anything at all non-standard, which at that time included alternate fabric type, or color, or design features --- then she still sewed the tent herself. Which OTOH likely meant a longer waiting period, but one should expect that for a custom tent.
I have no idea about the others, and you probably just have to contact them individually to find out. For that matter, I don't know if it's the same story still for Lightheart.
In a way I think it's kind of a good sign when a cottage vendor moves production to China or similar, because it's a sign that their not-well-advertised product is too successful for local production to make sense anymore.
I certainly do understand (and share) the desire to keep jobs in the U.S.; I can only say to that that few or none of us really know all of the dynamics for the cottage vendor. I've met several cottage vendor owners/founders, and not found a one that didn't seem like really nice people.