"Biden’s actual net worth is about $10 million, according to Forbes, which referred to him as “Middle-Class Joe” (though, in fairness, there’s nothing “middle class” about being worth $10 million)."

One of the things that struck me when I was studying political science in university was that "everyone considers themselves middle class" my professor exemplified this by saying he made $70,000 a year and considers himself middle-class while his brother-in-law made $700,000 a year and called himself middle class, and I knew my parents made $20,000 and considered themselves middle class. So it makes sense why every politician is always "worried" about the middle-class.