But here's the catch: that's what Americans thought a century ago. In today's money, that's about $20 million or so. So today, "rich" is anyone with a net worth of $20 million.
And below that? We have various gradiations, including upper middle class, comfortable, well off, and very well off. Then, finally, rich. I'm not saying I'm thrilled with this definition, but in the caste-driven psychotaxonomy of the average American voter, I'll bet it's pretty close to the truth.