> The counter-argument is that orange just means decaf to the customer
That might be a case of a trademark being genericized. Or the trademark should not have even been granted in the first place if orange meant decaf before Sanka started using it.
It didn't, though. Orange meant decaf because decaf (usually) meant Sanka.
BTW, trademarks aren't "granted". You can register a trademark, but you don't have to. Registering can help in a trademark dispute, but you can win without registering it, and you can lose even if you did register it.
That might be a case of a trademark being genericized. Or the trademark should not have even been granted in the first place if orange meant decaf before Sanka started using it.