Derek,
Of course, you are right.
At 3% per year, productivity changes over 45 years would account for not quite a factor of four. Therefore, the change in value of the money would be nearer $1 -> $0.11 or "only" a 9-fold decrease in value. It still makes silver a little bit dear to use for minting quarters! (Silver prices: $0.91/oz in 1960, $7.80/oz today; an 8.6-fold increase.)
Rich