Historically, the middle class has referred not to those who are close to the median in living standards, but those who are neither part of the ruling upper class, nor common peasants or laborers (working/lower class). In this sense, it's not contradictory for those who are in the top 5% or whatever economically to consider themselves middle class. There's been much derision of yuppies who consider themselves middle class proper, as opposed to upper middle class, but historically, that's exactly what middle class meant. It's not necessary for the middle class to include the economic median, nor for it to exist at all.
If anything, the definition has been diluted downward to include those who are part of the working class, I suppose, to reflect the spread of the bourgeois mentality and general increase in discretionary income and to accommodate aspirational self-assessment. Using a more historical definition, the median person in the United States probably qualifies not as middle class, but as working/lower class, just as the median person did when the term originated. Upper middle class seems to be a term made up to mean middle class minus working class people whom we feel like we have to call middle class because that's how they view themselves.
A big part of the right wing con has been making people feel they are better off than they are - having working class people feel "middle class" has probably harmed the progressive cause by allowing them to align politically with their aspirational peers, instead of their actual economic peers. Many of you may see Wil as delusional for not considering himself well-off despite being able to afford or take for granted a bunch of things that are out of reach for average Americans but I'm not sure that's his problem. The problem to me, is that I don't think he makes enough money to look down on community colleges, state schools,
public schools or retiring with a million dollars.