"extra-ordinary professor" is roughly the same as a "associate professor" – an ordinary professor is a tenured one (roughly). So no wonder Prof. Liebig wasn't happy about it.
They should have mentioned the Superfest glass (also referred to as CV-Glas or Ceverit) made in East Germany. It's still mindblowing it's not made anymore. I hope someone is eventually picking this up again.
Gorilla Glass is essentially the same thing, and it (or similar products from other manufacturers) is on nearly every smartphone and tablet sold today, so in some sense it's more widespread than it has ever been.
Another reason it might not have caught on for drinking glasses is (aside from being much more expensive to produce), when it breaks it shatters into a huge number of _sharp_ shards, whereas tempered glass shatters into mostly blunter cubes. You can get tempered glass drinking glasses at IKEA.