Yes, some of the big estates (above $5,340,000) paid a lot of taxes; some paid nothing; and those that did pay, paid different real percentages, as compared to "bracket" amount.
I linked how many, and how much, in my lead off post - here it is again: https://www.irs.gov/pub/irs-soi/15es01fy.xls
You are still protesting "the estate accumulated during relatively low income tax periods at the expense of other taxpayers."
I posted the top income tax brackets during the years when Americans of all classes were equitably sharing the wealth via progressive taxes — from 1936 through 1981 the top rate was between 70% and 94, averaging 80%, more than twice the top rate since 1982.
Here's an example of "at others expense" using hypothetical gross numbers indexed for inflation, and real percentages.
• Let's say from 1936-1981 taxes from millionaires at 80% brought $75 billion into the Treasury each year; other taxes brought $25 billion. All $100 billion was spent to maintain the security and infrastructure enabling U.S. businesses to operate and to make profits (there's not a huge profit in beachfront property in Somalia or North Korea).
• From 1981-2017 because of the lower top rate of 28% to 39.6% only %36 billion came into the Treasury from the millionaires; other taxes had to bring in $64 billion in order to spend the same $100 billion to maintain the security and infrastructure for people to make profits.
• So there's the first part of "at others expense."
• Those whose average annual income taxes dropped from 80% to 35% thus accumulated the 45% income each year to build their Estate "at others expense."