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There was a good deal of understanding of deflation in historical economics. Just not in recent times. See, for example, Adam Smith's Wealth of Nations for a great discussion of the effects of technological progress on an economy. (hint: deflation and long term the only people who gain are landowners... capitalists see a short term jump in profits, laborers see the demand for labor, and thus their wages, drop).
I don't think bitcoin follows the traditional deflationary model. Here is why.
Inflation or deflation is considered based on a monetary unit, such as a US$.
But what if the currency was instantly ad hoc divisible? Then the unit (bitcoin) is not material to a transaction, only the current exchange amount, which would in any case be computed at the moment of a transaction.
There should come to be no resistance to spending based on the appreciation through hoarding BECAUSE....
The ad hoc values for use of this currency will see minute adjustments - discounts - which simply adjust for the disincentive to spend versus holding.