Virtually every other nasa mission has the same budget profile of expecting early failure so not budgeting in the costs of maintaining the mission.
That may have been the case decades ago when you were there, but you haven't been keeping up with the news - fully funded extended missions are now the norm.
But conventional ferric oxide tapes would have melted in the sterilization process, so they took a page from Hitler's scientists who pioneered magnetic recording on magnetic stainless steel tapes.
The use of steel tapes was indeed pioneered in Germany - but in 1924, while Hitler was in prison.
Radiation damage to integrated electronics in satellites was a big problem at the time, and I'm not sure why that's different now, but in any case they decided to use core memory rather than chip memory. (hence the term "core dump" for all you youngsters).
It was a known, and well managed problem, by the time the Viking's were designed.
Only this wasn't your grandmother's knitting style core memory but rather the cores were applied by evaporating the magnetic material onto the wires allowing a tight radiation impervious memory mesh to be synthesized.
That's called plated wire memory, and it was actually very common in aerospace applications.