Comment by kube-system

> Isn't this one of the most recyclable materials there is

It is! ... if it's unbroken, sorted by type, and in a place where there's demand for it.

Unfortunately, those advantages are often compromised by the recycling pipeline itself. Bottles of different types are thrown into trucks, and become unsafe shards of glass that are unsafe to handle and difficult to sort by type. It quickly becomes more trouble than it is worth given that the alternative is sand.