You make 'x' into a name for Mary. That this question should even arise is an accident of the considerable variability in equivalent formalizations of logic. All this is only to support the basic point, that is, names are never variables and variables are never names. It may very well be that, historically, variables evolved somehow from names. As for variables being primary, the fact is that in Russell's and in Quine's logic they simply are.
Names are at most shorthand for descriptions.
With the introduction of Kripke's theories of names, of course, this is all up for debate, but I believe it remains uncontestable that any logic is as it is defined to be and in Quine's elementary logic, names, if they have any place at all, are derivative of variables. Help me out. I don't see any connection. English is as much a mystery to me as it is to every lexicographer and linguist. But elementary logic is another matter, and that is what I have been talking about.