The reality is that the loom, for as amazing as it is, is only a small piece of why that item costs so little.
Tunic, possibly wool or linen. Both of these items still come at a massive premium today when compared to a cotton or a synthetic. We have made changes and massive progress in the production of the base materials.
We have transport issues, it is unlikely that your typical tunic was an imported good. It was probably made and sourced much more locally. Today, due to the nature of production and the structure of tax and tariffs on garments it is likely that your t-shirt is fairly well traveled, with it crossing the ocean more than once (cotton to Asia, woven in one place, made into a garment in another, possibly printed on in a third before even making it to you).
There is a LOT more to the story, sewing machines, zippers (YKK is a fascinating company), elastic, pattern making, fabric cutting. The boxes that your products are shipped in, cardboard and steel, the packaging plastic - the inks for it. Dye is a whole field of science and research that has made so much progress in the last 50 years never mind going as far back as a "tunic".
The point is there is a massive iceberg under that loom, one you barely see or think about.