When a significant part of the population pays no income tax, that's a problem. Despite assertions to the contrary in this thread, middle class people aren't paying 30% of their income in federal taxes.
Well I'm 20%. I just looked at a paycheck. So it came out to 19.6% I have paid so far of my income for federal taxes when you include SS and medicare (I am currently contributing 12% to my 401k - I don't expect anyone to be impressed by that, I'm not, I could do better . But taxes would be higher without that). That's overall, not marginal. I consider my income middle middle class for living in California (it's not cheap to live here, I mean sure this income might be ALL THAT somewhere in the country but ...).

A 60k income for a family would not be easier to do here, it's doable, it's just tought. So if you want to rent a house that's 2k a month, 3k to buy. Noone on a 60k income has any business buying a house here (unless they have a good inheritence or something, then well sure, have at it). Sure you could rent a 1 bedroom for 1k, you want to raise a family in that? It's doable but if you go with the renting a house for 2k a month then maybe 500 a month in medical insurance to cover a family (and that's not the fanciest of plans). So your up to 1/2 your GROSS on housing and medical. Then are you saving anything, paying any taxes, food, car expenses etc.. Am I really supposed to be eaten up with envy if one of my neighbors is raising a family on 60k a year here and not paying a massive amount in taxes? It's not a great income, not for a family.