You change the facilities to fit the weapon - pre WW1 someone suggested to Jacky Fisher that the "Dreadnaught" should not be built as it would require new dockyard facilities - his reply was that he didn't intend to fight the enemy using dockyards................
Indeed. But in a
competition, when one bidder proposes a platform that meets the requirements and requires billions in MILCON (military construction), and the other bidder proposes a platform that also meets the requirements but requires a small percentage of MILCON. which one wins?
BTW, there are LOTS of examples of militaries making weapon decisions based on facilities constraints. For example, why did the RAF not buy Hornets? They are obviously far superior to Harriers. Because that would have required the Royal Navy to build MUCH larger aircraft carriers to operate them from. The RAF was/is constrained to operating Harriers at sea because the RN was/is unable to obtain the "facilities" to operate much more capable fighters. Why did the US Navy take so much longer than USAF to fully enter the jet age? Because their wooden decked carriers could not handle jets. Why were USN ships of ALL kinds constrained to a maximum beam of 108 feet for decades? Because the Panama Canal is only 110 feet wide. Facilities constraints have influenced if not outright driven military procurement since the beginning of organized militaries.
On a side note, have you heard the story of how Roman military design constrained the design of the Space Shuttle? Really!