Unlike sewing, fabric manufacturing is mostly automated

Fast fashion still uses fabric rolles as raw materials.

The fabrics used in fast fashion are chosen for cost and workability, not durability and environmental impact.

premade fashion does produce fabric waste, it’s unavoidable. However, the waste is lower than self made clothes due to the differences is production volume and optimization.

If you make your own clothes, you get to choose better materials, remove at least one step from the chain of exploitation, and learn how to repair your own clothes along the way.