Maybe a hint?

In research software (my area) the majority of funding is allocated to time bounded projects. This often leads to a new bit of software being written for a specific purpose, which will then be minimally maintained for the next several years. If it is still being used but becomes difficult to run, then a new project usually ends up forming to implement a new version, which often will change several things to reflect newer requirements.

This probably isn't helped by research organisation often being used to running very old code, as often it is needed to reproduce results from a previous study.