Yeah, we read about something like that in economics. It's called the Law of Diminishing Returns, I think. One of the examples was that if you keep adding employees, at some point the output will start decreasing rather than increasing.
Pretty much. Same rule is also known as the "Law of Increasing Costs", which is more applicable in software development. Big development teams have a hard time collaborating fully; for some software, the ideal team size is one.
However, its even worse than that because, as a project advances, it costs more to bring people in because they need to learn more about the project to be able to do anything useful (or even just to no break things). So wehn an advanced project is behind schedule / has problems, the LAST thing you want to do is bring in more people.
Point being, I don't see Bethesda doing any hiring until they get patches and DLC out the door and are ready to start on something new.