Re: They don't build them like they used to
TBH that is a bit of a half-truth. Its design lifetime was a heck of a lot shorter. They built rock-solid so it would survive the Van Allen belts, cosmic rays, residual molecules and the occasional dust particle.
What they never predicted was that during its design life, Earthbound technology would advance so much. Massive improvements in ground-based comms equipment, plus power-saving software upgrades, are the true secrets of its longevity.