You really don't need to be wealthy to get a platinum card. You don't even need to be breaking six figures. You just need a good credit score. That perception is all hype.
That's how it is here in India. They tried pushing it like "prestige", didn't work. Now they just give it to anyone with a half decent salary and a willingness to be okay with the annual fee.
What is the difference? I have always believed the terms to be synonyms, and the Wikipedia article for "charge card" does nothing to change that impression.