Invented in the industry-rich but resource-poor socialist German Democratic Republic, Superfest glasses were designed with the aim of making them last five times longer than ordinary drinking glasses. Glass retailers depend on their products breaking - this new idea was a threat to profits. The problem with the original Superfest glass is that its manufacturers worked with modified alumino or borosilicate glass, which is not as easy to recycle as the more common soda-lime glass.

Source: Smashing idea: how East Germany invented ‘unbreakable’ drinking glasses