Median household income on its own is an irrelevant fact. It is only relevant in context of median household expenses. By the fact that household debt has never been higher, I think my point stands - even people earning $70k/year are living hand to mouth because their expenses have risen to $69,500/year, if not higher.
1) Note that I indicated that the 20% increase was a real increase and not a nominal one. That means that to the extent that household expenses have increased, it's because households are using their newfound wealth to purchase more/better stuff! That's not a hollowing out of the middle class, that's a prospering one.
2) Household debt has declined significantly over the past 15 years:
