"Using MY trusty inflation calculator, what cost 30 cents in 1964 costs $1.81 in 2005"
And what is so significant about 1964, other than conveniently supporting your contention? Want to try 1980?
The price of regular gasoline in 1964 was actually $0.30. That is the same number the economist used for 1950. What's so hard to understand about that.
The price of regular gasoline in 1980 was $1.19. That's not the same as $0.30.
These prices are listed in the link I provided.
The real question is why the economist chose 1950 instead of 1964 where the price was actually $0.30. My answer would be his inflation calculation works out much more favorably for him to weave his tale by going back to 1950 instead of 1964.
Here's a couple questions for you, do all commodities have the same inflation rate? Why not?