Here are some numbers that make sense using constant 2009 dollars:
Household income change from 1967 to 2009:
-the percentage of the households making under $35,000 went from 43.6% to 36%
-the percentage of the households making $35,000 to $75,000 went from 42.2% to 32.6%
-the percentage of the households making $75,000+ went from 14.4% to 31.6%
By 2009, $75,000 wasn't so good if you want to be considered middle class. If you are single, that's a decent income. If you are married without kids, you can get buy. If you have kids, you cannot save on that kind of household income, much less pay for college, take vacations, are put aside a significant amount of money toward retirement. Depending on where you live, $100,000 is probably the minimum amount of income where a family can be considered middle class. By middle class, I mean being able to save some money, take an occasional vacation, have health coverage, and eventually be in a position to put a child through college without going into debt.
I'm dubious as to using government figures of "constant 2009 dollars" because the figures are based on how government defines inflation through the consumer price index. Health care insurance, rent, and education expenses have skyrocket the past 15 years and aren't sufficiently factored into the formula in my opinion.
So the facts you presented above appear positive, but they are based on the governments calculation of the CPI.
So 17.2% of the population moved from the lower class and middle class to the upper class in 42 years. That is good economic mobility given the negative effects that unions, farm subsidies, various licensing laws enacted by certain professions, the Davis-Bacon Act, and the 1964 Civil Rights Act that led to quotas have had on the poorer members of society.
Again, $75,000 isn't the upper class. I'd argue it isn't even the middle class.
And while $35,000 in 2009 dollars might have allowed you to live a lower middle class lifestyle in 1967 for most folks, by today $35,000 in 2009 dollars qualifies you for EIC if you have any kids and other subsidies. In other words, you won't be paying income tax, you will be receiving refundable tax credits.
It seems to me that the frustration being shown by voters is aimed at government inefficiency and federal debt, flaunting of immigration laws by the current administration, the lack of accountability of politicians that violate laws, a Supreme Court that has traded upholding the constitution for partisan political beliefs, and the inability of the government to address the rising Islamic terrorist problem. Whether or not a person can make their car note, or student loan note payment each month, in my opinion, has a minimal effect on the frustration of the majority of voters.
Those things you enumerated matter a great deal, but so does economic reality. Approximately 50% of the population pays zero federal income tax and a large portion of that number is a net tax recipient. Over 40 million Americans are on food stamps. I think most school children in the US now qualify for free lunch. The bulk of the country is not more economically independent than they were 20 years ago. Go ahead and believe your numbers reflect reality. Then go to Walmart or the grocery store and take a good look around.