From a purely economical stand point, I would agree with you, but I would not draw a comparison between a riding a used bike and wearing used protective gear. Having said that, to each his own. I’ve witness many rider race with crashed leather and helmets, should they be doing that, probably not; but they do, so they will have to take that risk.
I guess may be for leather if you can visually see it in person and look at the condition that it has not been crashed and stitching is sound, then may be. but if you are spending $500 for a suit then why not just get a brand new one?