Spleenrippa
Yes, Right There
Military technology can be one of the most conservative fields there is. They invent marvellous things, test the living daylights out of them, trial them in the field, then maintain and support them with minor tweaks for the next 40 years. They were still using tubes/valves in aircraft up until surprisingly recent times.
As an avionics technician in the CF, I can certainly back this up. I work on one of the most electronics-loaded AC in the world, and half the stuff onboard was made in the '70s, or before. Stuff works (sometimes..), money is always tight and we manage to get the mission done anyway... Why buy equipment more often than necessary? 😛