I found it difficult to read the entire essay, so I didn't. I had problems with a lot of the characterizations.

To start, "What happens when, for the first time in history, adult human beings are free to have all the sex and food they want?"

This is only true for a subset of the people, but it's always been true for a subset of the people. When I read about the nobility of the 1600s, I see that there was a whole lot of sex going on, and surely they had enough food for themselves.

The 1960s/1970s era of free love, after the pill and before HIV/AIDS and drug resistant venereal diseases was also, I think, more free than now. The author writes that HIV/AIDS is "manageable", for those with access to good medical care, but doesn't dismiss the point that it's not true that adults now are freer in their ways than (again, a subpopulation of) adults in the 1960s.

"let us imagine some broad features of the world seen through two different sets of eyes: a hypothetical 30-year-old housewife from 1958 named Betty, and her hypothetical granddaughter Jennifer, of the same age, today."

Home deep freezers weren't really available until after the Second World War, so that description of a 1958 era is one of food plenty, not food deficit, and that description is only true for a couple of decades.

"If there is anything “fresh” on the plate, it is likely a potato."

That's just not true. I've seen the pictures of the farmers in the late 1800s/early 1900s coming into town with their produce on wagons. There's more than just potatoes during the growing season.

For a real-world example, see http://www.foodtimeline.org/fooddecades.html , and quoting from Barbara Hubbard, Chicago Daily Tribune, May 20, 1956: "This is a treat for them, especially when they are served hamburgers, fruit salad, carrot sticks, and an ice cream bar for dessert. They consider this menu a real party and what could be easier for Mother. When the children finish their supper they usually go upstairs to watch Daddy shave and tell him about their day. Then he reads them a story and tucks them into bed. This gives me time to broil a steak, mix the green salad, and dress the baked potatoes with sour cream and chives."

So, the children have fruit salad and carrot sticks, and in addition to potato, the adults have a green salad.

On the same link, a menu from Family Circle, August 1957, includes corn, salad, and honeydew melon, and from Women's Day 1959 has tomatoes, vegetable salad, and a fruit basket. Both have more than just potatoes.

"Wavering in and out of vegetarianism"

As was recently pointed out to me, C.S. Lewis in "Voyage of the Dawn Treader", written in the 1950s, ridicules vegetarianism as being faddish.

It's easy to believe that the author created examples specifically to illustrate a point, rather than to describe real cultural trends.

What I see, when I look at the same events, is a move away from a conformist culture to a diverse culture. The moral strictures of church, class, race, gender, etc. are less binding.

Remember too the author writes for the Hoover Institute, a conservative think tank. As such, works from them are more likely to be aligned with conservative views, and not, say, rail against patriarchy.