It's insanely profitable to Boeing mostly, yes.

They held (still hold) most of the contracts for the operating silos to this day. All the equipment had to be designed to withstand a first strike nuclear attack from the USSR. Not necessarily like a direct attack, but a nearby attack on its equivalent sites. 15 missile alert facilities per base. 10 missiles per alert facility. Three bases. Total 450 operational ICBMs under the ground with predetermined coordinates meant to strike at the most valuable military targets of the USSR, China, etc. (used to be more but Peacekeepers and others were dismantled).

Boeing designed a ton of proprietary equipment for these sites. Since it has to be hardened to EMP, radiation, heat, vibration, etc. it's over-engineered (and probably done well since it was the 1960/70s before full enshittification struck). Proprietary equipment, most of it classified for national security reasons, has to be within very strict guidelines, etc. Boeing basically holds a pistol to the Air Force's head with this shit. They can demand anything they want. Which is, of course, the entire point to a lot of this stuff. Enrich private corporations.