But as for the D&D druid, it's really become a palimpsest, moving from a hodgepodge of history, some inaccurate, and "close enoughs," to a class repeatedly redesigned and refined. Like a lot of D&D tropes, it started off inspired by a couple different ones, then became its own trope.
If you really want to go down the rabbit hole path dependency, I think the name Druid is a far bigger example than Scimitar.
While the original druid was a mishmash of bad Celtic lore, there is barely anything Celtic about the class as it currently sits. It's equal parts nature priest, shaman, green witch and elementalist. Sometimes you can add Summoner/zookeeper to that mix. It almost feels too limiting to have a class that could represent a variety of naturalist faiths, traditions and magic under the name of one specific cultural example. It would be akin to having the rogue class be named "ninja"; it does describe what the rogue class does but it is too specific to represent the wide array of other types of sneaky characters the rogue class currently does. (And the class was renamed from Thief for that exact reason).
But I wager inertia will keep them named druid, unless there is some major Twitter outrage about it. The class is too well known by that name (and has spread to too many other derivative fantasy works) to adjust to a more culturally neutral term.