More like "mega's needling each other out of lucrative military contracts" amirite?
In a large Navy project with multiple complicated systems gives the opportunity for one of the megacorps to be an integrating contract. Instead of building everything (somethings they lack expertise in), it is cheaper for the integrating contractor to buy the parts from other companies.
Northrop-Grumman gets the contract (because they own the shipyard able to build the hull), Bechtel builds the reactors, the Radar is built by Raytheon, the launch system is built by General Atomics. The carrier's fighters are built by Boeing, Lockheed Martin or anther sub-division of Northrop-Grumman.
The same can be applied to the fighters in many cases.
Oh wait, we are talking about New Eden...
Still makes sense, especially if non-capsuleers attempt to source from relatively local sources to minimize the cost of logistics.