I think, you're right, defkondo - it is affluenza.
I was born just as the war ended and , yes, the 'make do, and mend' mentality was prevalent - not just from the war years, but it was the general ethos for everybody, except the very wealthy. Even they, were somewhat careful about unnecessary waste, and would recycle, what they no longer needed or wanted.
Growing up, I didn't feel deprived, even though my mother was a widow. I had similar experiences with crayons, or most other items, and I was unaware of people 'keeping up with the Joneses', which has now crept into our lives, (or worse, 'keeping up with celebs'!) I noticed attitudes changing in the 1980s.
Most of the hoard that I am kondoing is due to living on a small income and keeping things 'in case'. However, even though I now manage on a tiny income, MK has certainly persuaded me to use all the 'best' stuff, rather than leaving it to be skipped, unopened/unworn! Now, the things that bring me true joy, are those that cost nothing and are not always tangible.
Of course, as Mums, our downfall is the emphasis today, on being 'good enough parents'! Too often, we see that in providing 'stuff' - clothes, toys, treats, various activities, and equipment, because we are 'time-short'. Our time, after love, is the most valuable gift for our children.