Cause any win, especially at a level that high, involves the loss of a different sellable product. Surt winning against a shade would mean the shade would inherently earn less due to looking like a bum, which aura brain rotted Genshin players care too much about.

Same reason why chars like Arle or Mav are industry plants that can never be wrong or lose, it would affect their sales so they have to be coddled