I certainly see no logical reason to buy real jewelry if the fake jewelry looks the same and costs much less.
Resale? How often do you sell your jewelry, anyways? And, the fake didn’t cost you much to begin with, so you lost little even without reselling it.
Same with longevity. You’ll save much more even if you buy 10 fakes of the same real jewelry, that’ll last you as long as you need and cost far less.