“worn, washed and discarded after about seven uses”
Never in my lifetime have I ever worn any pair of jeans just seven times. For most of them I cannot even count how many times they were worn - usually worn until they were “worn out”.
Again, “fast fashion” is, like “fandom” another thing not far very far removed from idol worship.
The real problem is washing them too much. It is OK when they stand in the corner by themselves. If you call them and they walk to you it is time to wash them.