In my job sometimes I saw price goods from high fashion after produce, final production costs are not that high for most goods.
Prada is still popular during in strange circles people, for example when read reports about politics/financial scams, when their describe what gangsters wear very often mention Prada.
Moreover, a lot of young girls bought the mini skirts. They send tons of clothes for influencers. They know that the majority of their customer is uneducated and don't care about quality and eye-catching design.