For bitcoin to be used as a store of value and a medium of exchanging for goods and services, It must be stable like others currencies.
What stability? What "other" currencies? Fiat currencies? Fiat is the worst store of value.
This is the purchasing power of the U.S. Dollar from 1913 to 2013, and it is contantly sinking.
that doesn't tell the whole story. "purchasing power" has obviously dropped by a huge magnitude because it's priced in dollars. that doesn't account for wage/income growth, which offsets drops in dollar purchasing power for consumers.
to clarify:
the per capita net annual income in 1920 was $223.87. based on what source you look at,
the average wage for workers around that time was $1300-1400/year. in 2016,
the annual median personal income was $31,099.
so while 1920 dollars were worth 12x more than 2016 dollars in terms of purchasing power, wages are also 23x higher in 2016 than in 1920. that's why it's important to consider wage growth and cost of living in addition purchasing power.
also, not only are markets fickle, but we can't generalize across all commodities and goods. prices have not risen so significantly in many markets. for example, in 1920,
the cost of a dozen eggs was $0.78. for comparison, last month,
they cost $1.19 per dozen.