The name "Coke" has evolved into a generic term.

It's pretty odd that they were able to trademark "Coca-cola" in the first place, as coca and cola are the two active ingredients. If I'd invented vichyssoise soup, I'd have been able to trademark "vichyssoise" but I bet no-one would have given me a trademark on "Leek-potato". Presumably they were later (1930) allowed to trademark "Coke" on the basis that it no longer contained any cocaine, but not "cola" because it's still a descriptive term: the stuff may well still contain cola.

FWIW, "coke" is fairly well-entrenched in the UK as a generic name for cola, but I haven't heard it used to mean soft drinks or pop in general. I've only once been asked "Is Pepsi OK?", but that may be because I mostly drink beer

Peter