“The wages in other countries are still lower than the absolute wages here, so products that lend themselves to more U.S. production are generally more highly automated,” Ms. Gloeckler said.

That has drawn criticism from some suppliers. Price targets “barely cover the cost of the fabric required to make the garments, never mind the salaries and expenses of American workers,” wrote Christopher Dal Piaz, president of the sportswear company SML Sport in New York, in a letter to the Walmart merchandising chief after a frustrating buying meeting. The machine-made products on which Walmart is focusing “do not build a new middle class,” he wrote. (Walmart says the effort has drawn pledges from manufacturers to create more than 1,600 American jobs.)

The average price of a garment sold in the United States is $13.49, according to the NPD Group, an industry researcher. That low price is largely a result of sales at extremely low prices by huge retailers like Walmart, Target and H&M — sales that are made possible by efficient supply chains and purchases of products from low-cost countries like Bangladesh and Cambodia, said Marshal Cohen, chief industry analyst at NPD.

But keeping costs low, which consumers now expect, can often mean lower quality.

“In many cases the product that we buy today does not have the same, higher level of standards that we saw in earlier years,” Mr. Cohen said. “Are you buying a T-shirt that’s lighter than it used to be? In many cases, absolutely, yes. They had to take things out to keep the price the same.”

As some consumers look for higher quality, the door to American-made goods seems to be opening wider. But even at the higher end, companies like Keff NYC say the market is too new and uncertain to bet on the future. Mr. Schiffer, the company’s chief executive, said a lot of companies were still just testing the appetite for American-made goods. After all, it is the shoppers who will make this movement succeed or fail.

“We’re not under any illusions,” he said. “We take orders as we get them. If people come back to us with reorders, great.”