See the Capitol Hill Baby Sitting Co-op[1] for how real life hoarding of stores of values mean that exchange completely stops. It is a classic currency story.
[1] https://en.wikipedia.org/wiki/Capitol_Hill_Babysitting_Co-op
[1] https://en.wikipedia.org/wiki/Capitol_Hill_Babysitting_Co-op
https://blockchain.info/charts/estimated-transaction-volume-...
I love how Bitcoin is destroying all these economic "theories".