Spending trends were sufficient to refute the OPs assertion.

To go deeper, take spending (here's another link - https://www.pewresearch.org/fact-tank/2017/04/04/what-does-t... basically 65% of federal spending is now for social welfare, rising from about 5% of GDP in 1970 to 15% of GDP in 2016) and add in who pays the majority of taxes (the top 20% pay almost 70% of taxes https://www.pgpf.org/budget-basics/who-pays-taxes).

The progressivity (rate of upper income taxes vs lower income taxes) has also increased in the time period. https://en.wikipedia.org/wiki/File:Average_US_Federal_Tax_Ra...

So the upper classes pay more taxes in both rates and absolute dollars, those rates have increased, and the social welfare programs are the largest and increasingly largest categories of spending.

See also the growth in income of the various quintiles after taxes and transfers, and the trends over these decades: https://www.cbo.gov/publication/55413#section2

To credibly assert "Post 1970s...austerity for the people, largesse for the military, corporations, and ruling class", you'll need to provide some strong opposing facts.

To reiterate and clarify the point from my original comment, you need to ask why and to what effect spending is done. The population of the US is much older and much unhealthier today than it was in 1970 and healthcare is more expensive. So increased spending on healthcare doesn't necessarily prove an increase in commitment to serve the people and can instead simply be a result of rising costs.

Also that Wikipedia link you included conveniently doesn't start until the very late 70s just after the top rate saw a huge drop from the levels established in the post-depression era.

Lastly you need to factor in growing income inequality in these numbers. It is possible for the top tax bracket to collectively pay both a higher share of taxes in both percentage and absolute dollars while each individual person in that tax bracket sees their tax rate decrease.

If I used to give 5% of income and now I give 15% of income, my commitment has increased, even if the need has also increased. 5% GDP to 15% GDP shows a pretty dramatic increase in commitment, especially with the economic growth in that time frame.

OP asserted "Post 1970s", so starting in the late 1970s is the appropriate starting point (quibbling?).

The progressivity rate link above was tax rate, not percentage of taxes paid.

Let's say I paid $500 per month in rent a decade ago and today I pay $1500 in rent. What does that say about the quality of my home today compared to the quality of my home a decade ago? It says nothing because there are countless other details being ignored in that equation.

OP's point was that a change was made during the 1970s. You therefore need to look at the period before the 1970s and compare it to after the 1970s. You were just looking at the time period after the largest change in the top marginal tax rate was already made. Here[1] is the top marginal tax rate during a larger time frame.

[1] - https://commons.wikimedia.org/wiki/File:Historical_Marginal_...