[aerophilic]

They insist likely due to the “Kleenex” effect. Couldn’t find a good reference, but once an item becomes generic, it can loose copyright.

Article: https://www.nytimes.com/2019/06/24/smarter-living/how-a-bran...

[bigstrat2003]

Not copyright, trademark. Two very different things, with very different laws.

[zuminator]

Sure, gp misspoke in saying "copyright" but correctly linked to a relevant article about trademarks and was correct in the sentiment that owners of widely used brand names need to be vigilant about their intellectual property.

[elsjaako]

You can find a reference by looking for "generic trademark"