In a utopian world with little to no waste associated with clothing, there would need to be a significant de-emphasizing of production and a focus instead on repairs, alterations, and upcycling or downcycling. Clothing is one place where this could be done with perhaps less innovation than other items. Decreasing the production of new garments would be the most significant change to the current way of doing things, and also one of the most impactful. If there is less new stuff being produced, choosing to alter, mend, and pass down or acquire second-hand clothing would be much easier. The best way to encourage all of these practices is to make them the easiest option for individuals.
Corporations are another situation. In our current capitalist system, corporations would likely be unwilling to produce significantly less, even if they could sell it for more. If the goal of businesses was instead to produce valuable and useful items rather than just make a profit, there would likely be a lot less resistance to a high-quality low quantity production approach.