I've been unable to find a single internet reference to any default provision of a Quit item in the Finder menu in any version of OS X, yet I've found pages and pages of results explaining how to
add such an item via Terminal. When such a result has included comments, not a single commenter has claimed to have had a Finder Quit command as part of a default installation of OS X.
I went looking for evidence from the horse's mouth, but found no references to a Finder Quit command—or the absence of one—in the admittedly meager documentation regarding the Finder at support.apple.com. However, an
image search there was somewhat more successful: assuming that screenshots posted by Apple to illustrate fundamental concepts are taken from plain-vanilla installations, there's no Quit to be found in the Finder menu in
Leopard,
Lion, or
Mountain Lion.
I can only suppose those in your informal survey either share customizing inclinations similar to your own or in fact were at some earlier point persuaded by your exposition of the benefits of having a Quit option in Finder.
