Generally not the worst assumption, but these guys have been around for a decade plus

This isn't a group looking to make a potentially one-off product in an attempt to break into the industry. This is a different marketing and manufacturing model that is trying to mini-max the cost-to-quality ratio by only making products that have already sold. Similar production quality as other selvedge denim companies like APC or Iron Heart, and sewn in the US. The fabric they source is often of limited supply, either discontinued or small production runs, from high quality mills.

The Five Brothers Shirt which I was gifted when I was down on my luck and just out of the service was made in a quantity which allowed a friend's aunt to purchase 4 of them as gifts for all the younger folks at her Christmas party that year, and there were quite a few on the sales floor at Sears when my folks took me school clothes shopping each year.

They are still in business, but I wonder what changed when the last time I looked at their shirts, they were north of $150, and now they are quite competitive in price, and I worry about the quality as is being debated in this thread.

Still have that shirt, four decades later, and still wear it around the house, though it's a bit frayed from rough work chopping and hauling firewood when I was younger.