re: You can't really compare the Viking missions with current ones
I was not comparing costs; I was contrasting missions over a >30 year interval.
In the 30 years since Viking many items have decreased in cost or alternatively delivered much more bang for the buck. NASA has made minimal gains over that period. Contrast the scope of this 2008 mission with Viking's. Never mind that the V mission planners did not have any prior Mars orbit/landing experience to draw from.
Contrast ISS bang per buck with SkyLab's.
Where NASA has continuously improved is with the science yield from their astronomical observatories.