Missing, not for the first time in such essays, is discussion of normal forms, particularly for the operational data. If one moves to SSD, response time factor changes significantly, even compared to short-stroking. But doing so with the typical flat-file datastore is cost prohibitive. In order to get maximum user data back and forth with available IOPS, one needs a high NF datastore, which also happens to have the minimum footprint on storage.

Coders just love to refactor code, but they (all too often in control of database schemas) refuse to refactor data. Since their schemas start life as byte dumps manipulated by their wonderous code (just like their granddaddies' COBOL/VSAM apps), refactoring data means re-writing code; well, mostly discarding lots of code. The lifetime employment assurance disappears.

IOW, the problem isn't technical, but spiritual. Much the same thing happened when the 360 appeared with DASD. Rather than code to Direct Access, coders continued to do what was comfortable, code to Sequential Batch. Who said there's something new under the sun?