I'm sure the qualifications to obtain a platinum are pretty minimal. The card colors are not decided by credit rating or income, but rather by "how much are you willing to spend for these benefits?" I never saw a fine print income requirement. I know the annual income required for a Chairman is pretty low, like $15K.
My annual fees are coming due at the end of this billing cycle. Every day I come very close to downgrading my platinum to Rewards Plus Gold. Right now I'm paying $395 for mine and $175 for my wife. For that money, I can downgrade to RPG and get her and I both a Chairman card (when it comes available again). I really think RPG is the sweet spot for cost vs. benefits.
I travelled a lot on NWA this year and made good use of the lounge benefit, but the other stuff I don't really use. Many of the bennies are provided by any Visa Signature or World MC. Maybe if we take a cruise or something and also get a retention bonus it might be worth keeping.
Honestly, if you're looking for status from cashiers and waitresses, get the Amex Platinum Cash Rebate card or USAA Amex. 99% of the public wouldn't even know the difference and you save yourself 395 bacon cheeseburgers.