the us largely does not charge for bags directly, they are a consumable that is part of the store’s customer overhead. At cost each bag is around 3 cents, and probably holds 15 to 50 dollars of merchandise that is being sold at around 2% net profit generally.
people often keep the bags and use them for other stuff, like trash bags or plastic linings or makeshift gloves. not everyone does. it’s wasteful, yes, though on net carbon impact it’s probably lower than plastic reusable bags and many plant fabric ones given a plastic industry exists anyway.
there is not a single thing that could wipe out a deep sea habitat that wouldnt also wipe any space colonies. but i dont see anybody arguing for that, despite being far more achievable and practical. also, there is no feasible way for space colonies to be self sufficient anywhere in the near future, so wiping out earth also wipes out space colonies relying on it for supplies. this argument aboOt survivability is absurd.