But really there's all kinds, from "we don't want this guy who insists on keeping the old C++ codebase alive" to straight-up people who engage in fraud because they think the company owes them.
That said, my personal view is that you should keep "legacy employees" unless they explicitly refuse to work.
Yup, even if they're no longer productive in terms of code output, it's worthwhile keeping them around for their knowledge of the systems - you cannot replace that, and if you try, you end up having to either 'archive' their work with a big "we don't know how this works, but it does so do not touch", or re-engineer it from scratch which is very expensive.
But really there's all kinds, from "we don't want this guy who insists on keeping the old C++ codebase alive" to straight-up people who engage in fraud because they think the company owes them.
That said, my personal view is that you should keep "legacy employees" unless they explicitly refuse to work.