Comment by benoau

My library includes games I played with my father and games I played with my own children. Given the option my children would certainly revisit their favourite titles with their own children one day, or for their own nostalgic memories.

One thing you are missing with your logic is that "throw it out" is probably more like "give to charity", the unwanted goods are not necessarily being destroyed and may be redistributed to people who do value them. If my kids didn't want my Steam account I'm sure there's others who would, and preservation groups and museums that would probably take it.