I looked at the chart in the linked Web page. To me, it's a confirmation of what Bernicke found regarding spending patterns of geezers. I borrow the following paragraph off FireCalc's description of its spending model based on Bernicke's finding.
Ty Bernicke's Reality Retirement Planning: A New Paradigm for an Old Science describes extensive research showing that most people see significant reductions in spending with age (not related to reduced assets or income). If selected, this option will reduce your inflation-adjusted yearly spending by 2-3% per year starting at age 56, and then stabilizing at age 76 to keep up with inflation. You should read his article for details if you plan to use this option.
The chart in the OP's article shows that other than for housing and utility bills, spending goes down in every category after the mid-50s. As most people do not retire in their 50s, the reduction in spending is not due to lack of income. People in this age group are at their peak earning years due to work experience and job seniority.
I know that I spend less in all categories except for housing (2 homes now) and travel, but not everyone cares to travel. The chart shows that pre-geezers spend less even on food and drink consumed at home, not just on eating/drinking out. And we no longer care to buy expensive clothes to impress, for example.
So, now that we have more money to "buy pleasure", we care less about it. I am trying to slow my own inclination somewhat by trying fancier food and drink, but it's tough to spend more. Following are a couple of examples.
A couple of days ago, I felt like having an after-dinner drink, but did not think of packing a bottle of Cognac with me on this road trip. So, I went to a local grocery store, and looked at what they had to offer. There was a common brand of French Cognac on the shelf, but the price was higher than what I usually pay. Then, I saw some American brandies at very reasonable prices. I had tried a couple of American brandy brands in the past, and did not like them. But that was 20+ years ago, and I am willing to try again. The bottle I bought was not bad at all! Did my palate get duller with age, or was it that American brandies were getting better? I think it was both. The net result: I can be happy while spending less.
Here's the 2nd example. In a recent road trip to a resort town, I researched on the Web with Yelp and Urbanspoon to look for a good restaurant. There was this one that was highly rated by hundreds of reviewers, and was ranked head and shoulders beyond everything else. We went there, and were sorely disappointed. The food was not bad, but perhaps our expectation was too high. My wife commented that she could cook better than that, and I agreed. Why were we so out-of-sync with the crowd? Anyway, because while high prices usually mean better service they do not guarantee better food, we are not crazy about going to expensive places, even if we can afford it.