plenty of American t shirt manufacturers still, Alternative apparel has a few US lines as well as American app. and All American clothing co., and there are plenty more with every fit and finish you can imagine, and not all of them are skinny boy fashion shirts that cost an arm and a leg either. problem is with scourges on society, er um i mean big box places like walmart selling shirts for 3 or 4 bucks a piece no American manufacturers can compete for the average joe's buck.
After all how do you explain to a guy that the $40 t shirt or the $200 jeans will last 20 times as long as his made in Mexico or China shit clothing that leaches dye on the couch, fits about as well as a cardboard box and most disappointing of all, falls apart after a few washes.
That said, there is a groundswell of people, myself included, who go WAY out of their way to buy American made clothing whenever possible. Jeans for instance, sewn and produced here with Japanese or US denim fit, look and feel much better than shitty Guatemalan made wal mart pants and they don't fall apart after one season. I typically buy one pair of jeans every 2 or 3 years and wear them every day until they are falling apart, upon which time the store you purchased from will repair them for a small fee or no charge. They can repair holes and tears as they have the ability to remake fabric where it is worn through even, good luck getting wal mart to do that for you. Pay the money and get something that will last, will look great and will give you a sense of pride.
duty now for the future if you will.