Even before current RAM price craziness ECC UDIMM's were hard to find, and often more expensive than non-ECC. I was lucky to grab 128GB for similar price to non

Even before current RAM price craziness ECC UDIMM's were hard to find, and often more expensive than non-ECC. I was lucky to grab 128GB for similar price to non-ECC a few years back. More people would use them, if they were available. RDIMM's do not work on normal consumer boards, so obviously people won't be using them.