I get what's happening, but it's strange to see it happening.
Actually, could I sell it for ~10% less than someone would buy it new? Is there a market for used Pis? Maybe 30%, I don't know. That I can sell it for what I got it for at all is wild.
We just aren't making enough stuff to keep up with demand.
This kind of thing has happened before.
Some computer-oriented highlights from the memory hole: An epoxy plant burned in 1993 that had supplied ~60% of that stuff for semiconductor packaging which caused widespread issues, there were aspects of RAM shortages in middle 90s (mostly because Windows adoption increased demand), we had Thailand floods that screwed up hard drive production, we had the crypto boom affecting GPUs in a big way from ~2016 to ~2022. There were covid-era chip shortages (which had been rationally predicted years before the covid scramble) while the Chia crypto bubble also ate up storage devices around that time.
It sucks for consumers (read: buyers) when this stuff happens, but it's been pretty normal for a really long time.
The current shortage is due to hugely-increased demand in the datacenter space and that's a new problem, but it's just one in a long list of problems that had been new when they surfaced. :)
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Anyway, yeah: When prices are high, it becomes time to go through the pile of hardware and sell some stuff.
BTC has been an ASIC game for a very long time. GPUs haven't been profitable there since the ASICs showed up a dozen or so years ago (with odd exceptions where power is "free").
Eth kept hitting the GPU market hard until ~4 years ago, when the network switched from proof-of-work to proof-of-stake. That cut the home-gamer hobbyist miners out rather completely.
(That last one kind of sucked for me. When my office-room had resistive heating, I rather liked getting paid for my otherwise-idle GPU to make heat for me in the winter time. It wasn't much, but >0 is more than <0.)