Like the anecdotal evidence from the Great Depression didn't tell us this the better part of a century ago?
The bummer in proving it, is that it is self reinforcing, we live in a particular kind of world, it values pretty stupid things (stuff), and when we don't think we have enough stuff, we internalize that as not being up to snuff. Change what we value and you change the entire game.
I've always told the kids that anyone can buy stuff, and respect is earned not by the size of your wallet but the attributes and skills that you can't buy. The fastest runner, the best ball player, the honest and fair, the caring you display and demonstrate, the understanding and insight that goes with a decade of study and experience.
Any moron can whip out a check book and buy a new car, and many do. Anyone can have a car bought for them by their family and pretend it increases their stature within a group, but it only works if everyone else falls for the stupid idea that your place on the socio-economic scale is determined by stuff you have, rather than who you are, and what you are good at.
Obviously, these ideas don't fit in well with those handing out participation awards so everyone can be special, because to be good at something, you are quite often better than most of those in your social circle, and competition demonstrating skills beyond the norm isn't to be appreciated. It screws with the meme. But it does turn out, as kid #1 understands very well now, to be very valuable when you go into the real world and competition is exactly what it is all about. There are 5 jobs available, and 100 people applying, and it isn't those who show up to just participate, or who's mommy and daddy bought them a car, that get them. But maybe when they realize what a load of crap they have been sold, and are unable to reverse course and get around that lifetime of habit, well, depending on how hard they take it, offing themselves is suddenly an option.
Our world, so full of precious snowflakes nowadays...