One of the most popular toys for Christmas 1978  was Hungry Hungry Hippos. In 1978 it sold for $8.99  – which is $33.47 in 2018 dollars (using the CPI ) or $27.04 in 2018 dollars (using the GDP deflator ). Today Hungry Hungry Hippos is available at Walmart for $13.99  – roughly half the real price of 40 years ago.
And I’m pretty certain – although I cannot prove – that the proportion of American children who would today be excited to receive as their main Christmas gift a Hungry Hungry Hippos game is far smaller than was that proportion in 1978. The reason is not that American children have become ungrateful; rather, it’s that our society has become so much wealthier since the late 1970s that mechanical toys are no longer valued as highly as they were when Jimmy Carter toiled away in the Oval Office.