Not it sure as hell does not mean one is "rich." It is, at best, an indicator of marginal affluence. It certainly is stretching the bounds of credulity to call it "merely" middle-class, though, and forget calling it "poor."
"Rich" means more than having a relatively high income. It means having the means to obtain in relative short order, or having already obtained, relative financial independence. An income of $100,000 doesn't qualify in most places. Such a person would be required to find some income if he loses his current source, and he would almost certainly suffer financially and take many hits to his credit during a period without income. This person isn't "rich" until he's amassed enough savings that he can weather such a period without significant risk to his finances or credit, which will take literally decades in most cases.
"Rich" means more than having a relatively high income. It means having the means to obtain in relative short order, or having already obtained, relative financial independence. An income of $100,000 doesn't qualify in most places. Such a person would be required to find some income if he loses his current source, and he would almost certainly suffer financially and take many hits to his credit during a period without income. This person isn't "rich" until he's amassed enough savings that he can weather such a period without significant risk to his finances or credit, which will take literally decades in most cases.