The Wall Street Journal has a useful piece describing current efforts by the different services to keep their budgets high by embracing new missions and demanding resources for them. One of the most egregious is an Army effort to have its helicopters on Navy ships to support soldiers on land. Of course, that's what Marine helicopters are for.
This is new but not surprising. When budgets are threatened, Pentagon planners repackage their wish lists. That's why everybody wants to have a cyber mission of some sort.
I learned this lesson back in the 1970s when the Senate Armed Services Committee staff looked into planning assumptions for war in Europe and discovered that both the Army and the Air Force assumed that only their service was responsible for destroying Soviet tanks, and they thus needed larger numbers of their own tanks or planes.
Some interservice rivalry is helpful -- in lowering costs through competition and giving senior leaders more options. But as this article shows, it can get out of hand.