In Korea, I have not seen any fabric shops like those in North America. There are quilting shops, but they are specialized, and tend to be very expensive if you just want to buy fabric. Fabric is sold in markets. Here are some pictures from the small market in the city where I live.
There are very narrow aisles, dividing little booths.
The booths are crowded, with a lot going on. I assume that each one is a business, and most people do some kind of custom sewing as well as sell fabric.
There are many samples of work, like curtains, cushions, aprons, etc. Each can be custom made with the fabric of your choice.
Of course, if you don’t want a product, you can just buy the fabric.
Most of the machines are more industrial than mine.
There are also beads, buttons, etc.
Cross stitch is very popular as well.
There is also knitting and crochet. Some people have large mats on there floor made of filet crochet.
Someday I hope to visit the market in Busan which is an hour away. It is similar but about 1oo times bigger. I have heard that the market in Seoul is one of the largest fabric markets in the world. It’s a bit far for a day trip, but maybe a weekend.