There are definitely issues where plant and polymers can be good substitutes but they often aren't as good. Plant based fabrics tend to have much worse perform

There are definitely issues where plant and polymers can be good substitutes but they often aren't as good. Plant based fabrics tend to have much worse performance than the animal derived alternatives. Granted, that doesn't apply to clothing being worn purely for fashion. Polymer based fabrics often do not wear well and may have issues with micro-plastics and outgassing.