I made less than $50K last year. Your definition of upper class would include me, and that's ridiculous.
Time for a bit of introspection, I think.
No, the idea that someone who makes $50k per year should be considered "upper class" is indeed ridiculous, no introspection required. A person is not "upper class" just because they make their money from real estate. To be sure. deriving wealth from investment rather than from working for an employer is part of the definition, but there are other aspects to consider. For one thing, the income has to be significantly above average, which is not the case here. Historically speaking, one's family background played an even larger part than wealth in determining one's social status—a merchant might be wealthier than the average aristocrat, but would still not be considered "upper class" for the simple reason of not being born into the aristocracy.