Why is NASA still using some equipment from the 1960s?

a
NASA has a fixed budget that is less funding than they had during the space race.
b
The machinery is efficient, so the next generation of engineers didn't waste time designing a new one.
c
Brevard county doesn't collect enough taxes for them to build a new one.
d
It has never broken, so why replace it. They built a very good product back then.