I doubt that is a "conspiracy theory" so much as fact as the Air Force chose the B-2 because Lockheed already had the F-117 contract even though the Skunk Works were the ones that originally proposed a long range stealth bomber which the Air Force then turned into a competition. So do not judge them too harshly, if anything criticize Northrop for their incompetence and failing at the development of an airplane that was deficient compared to the Lockheed entry and was originally proposed to cost $150 million or so. Honestly Northrop should never be allowed to develop another military aircraft again as the B-2 along with all of its problems and cost overruns only has a mission readiness rate of 47% or so compared to the average of 70+% of the entire fleet.
I would suggest you read the book "Skunk Works" by Ben Rich and Leo Janos if you are interested in the politics of military acquisitions and development cycles of the time. The book discusses the many inefficiencies and inflated egos that go along with procurement programs and the trend for higher ranks to want aircraft or ships that make them look better and advance their career. Also a well known aircraft design book by Daniel Raymer explicitly states that when designing an aircraft you need to keep in mind that given fairly equal performance a customer will always choose the more visually pleasing aircraft (see the A-10C and the "Warthog" nickname along with the military attempting to cancel the program for 20? years or so now). A few examples of this are the Lockheed stealth ship program and stealth aircraft carrier/sub designs. Ben Rich states that none of the admirals would approve the program because they didn't want the secrecy behind only commanding a fleet of stealth ships they can never show off to the world and do not advance their career... The stealth ships were built to defend the CAG's from aircraft due to DoD analysis of a full scale war with Russia predicting most of the naval ships and carriers being destroyed within 2 weeks or so I believe. Keep in mind this was in the 80's so I don't know if they have filled that defensive gap since then.
In the book Ben Rich admits the military would deliberately spread out military contracts to keep as many companies in business as possible instead of say, Lockheed monopolizing the fighter/stealth market and pushing others out.
Further reading would be "Kelly Johnson: More Than My Share of it All" by Kelly Johnson and (ghost writer). It does not have nearly as much detailed information on aircraft and development programs but he does discuss the aircraft industry almost from its beginning to late 80's and the shift of military commanders from high integrity to only wanting to advance their careers and push paper.
Most of this information is from the Skunk Works book and some other reading so I would highly suggest reading them yourself. It is a very insightful book. The Mach 3 autonomous reconnaissance drone launched from the SR-71's in the early 70's and overflying China is very interesting among other things.
P.S. My first post on the ED forums! Have to say I love the franchise and thought this thread would be a good place to start.