The idea that you can return unsold product to the supplier is a relatively new idea for most industries. When retail boxed software was at its peak (in the 90's), it wasn't very common at all.

I can't find anything current for boxed software (for obvious reasons), but boxed video and board games cannot be returned unless the retailer has a special deal with the publisher (rare).

https://www.polygon.com/2017/7/17/15974096/what-it-costs-to-...

https://www.ign.com/articles/2014/03/05/inside-the-secret-wo...

https://www.reddit.com/r/boardgames/comments/6asinu/can_reta...