He jumped around a lot in that, but as for foreign workers, I strongly suspect (without any real data available) that another dynamic is at play: That is, some

He jumped around a lot in that, but as for foreign workers, I strongly suspect (without any real data available) that another dynamic is at play: That is, sometimes programmers quit their jobs. And then an inevitable process of bitter condemnation of his code begins. This is a function of distance. Once your code leaves your protection, it's likely to be declared garbage. Foreign workers suffer this automatically.