Could be any number of reasons: 1) product wasn't selling 2) company rebranded the product line to something else (eg, changed name). 3) they dropped out of that business (eg, they stopped selling glasses entirely). etc.
Usually, in the case of a mega corp, if they stop selling something, it's b/c the corporate priority says that each product line has to hit certain targets, revenue numbers, etc, and if it doesn't it gets phased out.