The basic flaw in the article is that they used the Bank of England calculator, actually explicitily saying how it wasn't suitable, to then make the conclusion:

The basic flaw in the article is that they used the Bank of England calculator, actually explicitily saying how it wasn't suitable, to then make the conclusion: >What we can say, however, is that there are far more people who make $50,000 in today’s America than earned £700 in 1919 Britain. Agatha Christie claimed she wasn’t rich, but her income was far above average in 1919. In contrast, most American households earn more than $50,000. It is more likely that the "real" correspondence is to current 100,000-150,000 US$ today (after taxes).