Even DDR4. Just checked, I bought a non-ECC 1x32go stick for my homelab on August 25th, priced 78€ on Amazon. Same offer is now at 229€. Yeah I guess I'll wait before updating to 64gig then

It reminds me very much of the crypto mining craze, when there was a run on GPUs and one couldn't be had for any less than 5x it's MSRP. I know that eventually passed and so too will this but it still sucks if you had been planning to purchase RAM or anything needing it.

I don't think DDR4 is even being manufactured anymore, so the rush is clearing out that inventory for good.

It is still being manufactured. Older memory standards continue to be manufactured long after they stop being used in computers, e.g. for use in embedded devices.