Why is it necessary to buy clothes every 2 weeks and then throw them away after wearing them once? Certain externalities (e.g. environmental destruction) are n

Why is it necessary to buy clothes every 2 weeks and then throw them away after wearing them once? Certain externalities (e.g. environmental destruction) are not priced into these products - so it's about time that these fast fashion companies are being stopped from exploiting loopholes. Maybe this will encourage folks to use 2nd hand markets more, like Vinted or Deepop etc.