Still plenty of stay-home moms who raise the kids and make the home. I don’t think your comment about that way of life being outdated is accurate, and I predict that because of automation the over-all need for labor will decline such that we will necessarily as a society go back to breadwinners and caretakers working together to build a household.
That claim is 100% bullshit and I'm surprised anybody on HN would ever believe it. Just consider housing prices alone!
Where was that study done? Bumfuck, Nowhere, where a 2,000 sq ft house is $50K and you can live like a king on $30/hr? Was it done in 1990 or something?
Go to ANY major city and $75K/year won't even buy you a modest condo, let alone a house. You'll struggle to even raise a family in an apartment on that.
I can certainly tell you that I'm much happier making $200K/year than when I was making $100K/year. $100K paid all the bills and still had decent disposable income. $200K means I can buy a $2,000 GPU and not feel like I need to budget for it. $200K means I can buy my $150,000 dream car. $200K means I can buy prime-quality ribeye on a whim and not care that it's $30/lb. It means flying first class to Italy when I go on vacation, rather than flying coach to somewhere in the USA.
I can't fathom how ANYBODY can think the plateau happens at $75K. Absolute and utter nonsense.
I touched on the topic of housing. I think most families would be happier in a ~2000 sq ft house rather than a <1000 sq ft apartment[0]. Certainly you can accept that truth without needing a peer-reviewed study of people's housing preferences. You can't buy a 2000 sq ft house on $75K/year unless you're in the middle of nowhere.
[0] Note that I mean MOST, not ALL. There are some people that despise single-family homes and prefer the higher-density aparments/condos, but I think they're a minority.
I would argue that life satisfaction is much more important than happiness generally regardless.
Is that adjusted for COVID-era inflation? That number should be 20% higher, at least.
I call hard bullshit. Without even considering luxury spending, just not having to think about money very often is incredibly nice, and $75k is nowhere near any kind of plateau on that.
At $75k you had damn well better still be tallying up how much money's going in your cart at the grocery store. Not having to do that for basic stuff anymore, not having to worry much about coupons or bargain-shopping and just being able to say "I need this, or at least it would be very nice to have" and get it, no worry, no saving, no waiting for a sale, is such a GIGANTIC load off one's mind.
Car breaks? Take it to the shop, any plausible bill won't trash your budget for the month, let alone the year. Water leak? Yeah you could fix the drywall... but if you really don't feel like it this time, or are busy, you can just have someone else do it and the bill won't sting that bad. Groceries? Barely even pay attention to the total. Need some particular clothes for some purpose? Just buy them, and decent ones that won't look like shit and do fit right, at that. Kid breaks their arm? The cost barely even crosses your mind (it'll suck, but you'll be fine).
It is SUCH a relief.
Not being anywhere near as stressed, and spending at-most 5% as much time thinking and worrying about money as I did when we were struggling, sure frees up a lot of energy and time to pursue happiness, if not providing it directly (i.e. not even counting when I'm able to trade cash for things like free time to play with my kids or spend more quality time with my wife, let alone buying toys, which, hell, is also genuinely nice).
I'm certainly grateful every damn time we have some mid-tier emergency pop up and the part of my brain dedicated to money just goes "hm, that's a shame" and then shuts up, rather than screaming "OH FUCK OH FUCK OH FUCK" for a day or three. It'd be madness to suggest there's not a strong correlation between that relief and general happiness.
I think a true sense of purpose to life is likely to make someone far happier, and ironically money can't buy that. Same with most things really worth having.
If you can't infer from those peoples' behaviour money doesn't make you happy, I think you've got a long learning curve ahead of you.
Safety, improved-probability-of-continued-comfort, options, and freedom-of-action do great things for most people's happiness, and those are what money is.
If I were to venture a guess, drug overdose prevalence is high in some disadvantaged cohorts, not among well off or rich.