Who cares if it's a luxury good as long as it's not a positional good? If a larger group of people take, I don't know, out-of-town vacations or buy cool-but-not-very-useful electronic gadgets or take classes in glassblowing or firebreathing, then that's economic activity which in turn provides jobs for hotel staff, factory workers, and craftspeople.
Your single example is a university education, which is at least arguably a positional good. But tons of luxury items aren't positional.