Every few years, life insurance modelling circles back to a familiar idea: “Surely we can build this ourselves now?”

Open-source languages are mature. Cloud infrastructure is cheap and elastic. Numerical libraries are faster than ever. On the surface, the case for fully open-source financial modelling feels stronger than it ever has.

And yet, time and again, large-scale internal build attempts quietly stall, get re-scoped, or end up re-introducing vendor platforms through the back door. This isn’t because open source has failed actuarial modelling. It’s because life insurance modelling turns out to be much more than code.