Each era was a correct answer
Histories written to introduce a new category tend to treat what came before as a series of errors now corrected. That reading is unkind, wrong, and useless to the argument it is meant to support. Each era below was the right architecture for its constraints. The arithmetic really was the bottleneck when machine time cost more than planners did. The single database really did remove work that departments were otherwise paid to do twice. Renting the operation of the software really did solve the problem that the operation had become most of the cost.
The claim made here needs the generous reading rather than the dismissive one. If the previous eras were mistakes, nothing follows from them. If each one was sound, then the thing they all held in common is structural, not accidental, and it is worth naming: every era automated more of the record, and every era left the judgement with people. That is true of the calculation that produced a material plan, of the database that made one position visible across functions, of the rented infrastructure, of the specialist systems chosen on their merits, and of the drafting assistance that reached the work most recently. The interface changed, the cost changed, the reach changed. The person deciding did not.
Systems are named here, and named as fact. Where a name appears below it is a record of what shipped and when, carrying no judgement about the company that shipped it. Elsewhere the argument is about architecture, and naming a product there would turn it into an argument about a vendor.
- 01Material requirements planning1960s to 1970s
- 02Manufacturing resource planning1980s
- 03Enterprise resource planning1990s
- 04Client/server deliveryEarly to mid 1990s
- 05Cloud ERP2000s onward
- 06Composable and best of breed2010s
- 07Assistive AI2023 onward
- 08Autonomous resource planningNow
What changed technically
If the division between record and judgement held for sixty years, the interesting question is what moved. Four things did, none of them on their own sufficient, and three of them were produced by the eras above as side effects of solving something else.
The record inside a resource planning system has always been structured. What arrived at the company was not: the supplier note written in prose, the contract clause that qualifies a delivery date, the exception that does not fit a field. The boundary between the record and the judgement ran very close to that line, because the part a person had to do was usually the part that required reading something. Language models moved the line. That is a change in what can be interpreted, which is one stage of a loop with six, and it is the change most often mistaken for the whole of it.
Continuously operated software with programmatic access over the whole record, not an extract of it, is the inheritance of the cloud and composable eras. It is what makes it possible to read a position at the moment of the decision and write the consequence back into the same store instead of into a file somebody loads later. Neither era was built for this. Both were built to solve the cost of operating software and the fit of a module, and the capability arrived with them.
Identity and policy enforcement for non-human callers, scoped per action and not inherited from a user account, is what allows a grant to be written down: these action types, to this value, under these conditions, revocable. Before it, software acted with whatever a login could reach, and the only real control was that a person was assumed to be behind the login. This is the least discussed of the four changes and the one that decides whether any of the others are permitted near anything expensive.
Retaining what a decision was taken on, not only what it produced, is now an ordinary storage line, not a capital argument. Every earlier era economised on exactly this: the inputs were discarded and the resulting entry was kept, because keeping both was not worth what it cost. A decision whose evidence was not retained cannot be reviewed afterwards, so cheap retention is a precondition for letting software decide anything anybody may later question.
None of the four supplies the willingness of an organisation to answer for what software decided. That is a governance fact and not a technical one, it is settled company by company and function by function, and it has no version number. Nothing here predicts how quickly any of this is adopted, in what order, or by whom. The technical preconditions are in place, which is a different statement from the transition having happened, and the distance between the two is the quantity worth measuring.