The iMac had NVMe SSDs at least as early as 2015[1]. Apple has since moved away from NVMe modules and gone to raw flash chips hanging directly off the proprietary "T2" system controller chipset. I think it's fair to criticize the proprietary/non-upgradeable nature of this storage solution but benchmarks have shown it to be comparable in performance to standard PCIe 3.0 NVMe drives so calling it outdated is not really a valid criticism.
Not exactly a "major update". Looks like the magic on this iMac is already wearing off and the magicians want their reality distortion spells back.