A recent study established a link between financial resources and happiness ("emotional well being"), specifically noting that there was a certain amount of money beyond which happiness itself isn't improved. The dollar amount was a household income of $75K.
Yet, that $75K is a median number, meaning some might answer a low number like $30K, while a fewer percentage of population would say as high as $200K+. I am willing to bet the former group would include a lot of young people just starting out, and many people who are currently unemployed. And the latter would certainly include most doctors, businessmen, etc...
And then, if we are to conduct the same survey elsewhere in the world, will we be surprised to find that the median happiness number varies in proportion to the countries' median income?
The point is that we are all influenced by 1) our peers, whether we admit to it or not, and 2) our own current condition.
About the peer pressure, I just have a theory about my group of happy $20-$30K low-budget RV'ers. They may be so because they see the poorer RV'ers struggling on meager SS!
In my case, among the people I hang around like my former work friends and my relatives, I did not do too bad. Some maintain a higher standard of living than my own, but gosh, they are still working their butt off, while I goofed around for months on RV treks, before coming back to my stick homes, which are just a bit smaller than theirs.
I will describe a bit more about 2), the influence of own current condition.
Many of us who ER'ed claimed that we pulled the plug when we had enough. But how did we determine that level? What's your number? If your career is a highly-paid one, you will want a few millions, perhaps even 10 cool ones, to feel safe. Most people would be quite happy with a barely 7-figure portfolio though, and that is a function of what they have been able to save up to that point.
If our job were easy-money, we tended to want to do "one more year" to get more. But if the work condition got stressful, we would console ourselves that we did indeed have enough, and it was time to let go.
So, my conclusion is that in order to maintain our happiness and keep our desire in check, we want to look down, not up. For the decamillionaires, that means learning not to envy the billionaires' yachts.
As for me, I like to research my favorite low-budget RV'ers, because it is so easy to put myself in their shoes. After six months of getting lost in the woods, when I could not hack it anymore, I would go home and declared the experiment a success. Hey, even Thoreau only stayed at Walden Pond for 2 years, 2 months, and 2 days.
The idea of looking down is not for schadenfreude. That's just too mean. It is so that we feel lucky that we have it better than some even poorer chaps, instead of looking up and envying people who have more.
But I think we are getting too far from the idea in the article quoted in the OP. The idea is not about dropping out when one reaches a certain level. It's about not killing oneself in one's work, about not being too much of a type A, and not sacrificing family life, etc...
Nothing's wrong with that, but hey, that's just another platitude to us laid-back early retirees. What else did we drop out early for?