Clothes are inherently consumable goods. If you use them, they will wear out. If you do not use them, they still age over time. You cannot "copy" a piece of clothing without a truly astonishing amount of effort. Both the processes, and the materials, may be difficult or impossible to imitate without a very large investment of effort.
Compare this to digital art: You can copy it literally for free. Before AI, at least you had to copy it mostly verbatim (modulo some relatively boring transforms, like up/down-scaling, etc.). That limited artist's incomes, but not their future works. But in a post-AI world, you can suck in an artist's life's work, and generate an unlimited number of copycats. Right now, the quality of those might be insufficient to be true replacements, but it's not hard to imagine we'll be in a world not so far off when it will be sufficient, and then artists will be truly screwed.