I wish that hardware companies gave us the option of unplated brass!!!
You could polish it with normal polishing compounds (I love white diamond metal polish for the chrome on my bike!!)
And brass just looks awesome even with some patina on it.
I have had gold, which wore off the edges of the hardware while I was building the guitar. Black hold up pretty good, but the black hardware I have on my one guitar is wearing off on the edges and corners.
SO............
I have decided that chrome is the way to go for me from now on. Other than it being the most durable coating IMHO, it iis the cheapest choice in hadware. So my logic is it is cheaper and looks new longer.
Most of these plating problems come from the company doing the plating trying to cut costs. The stuff needs to be coated in two or three different types of electroplating materials. One of those is copper, which is expensive. The Chromium they use for the final coating sticks better to copper, which I am thinking a lot of guitar hardware manufacturers simply do not specify to use. Sometime research a quality reproduction bumper for an old corvette. They range in price from $250-1250. The $250 ones are dipped once, maybe twice with no buffing in between. The $1200 ones are usually triple dipped in all the solutions they get dipped in, with a buffing between each dip.
I guess I really didn't answer your question, but hopefully I gave you some insight on why this happens!!!
When all else fails buy hardware that is made in the USA. That goes for you non USA members, too. We have unions and pay workers decent wages. I find it pretty hard to believe that some poor Vietnamese worker who makes $0.35 and a bowl of rice really cares if the parts they are plating hold up. A U.S. worker has something to be proud of, a decent paycheck!! So those are my thoughts on that!!