Bitcoin can rely on the CPI only in the sense that Bitcoin *becomes* the CPI.  Like I've said before, if this type of thinking (which has been in use since WWII, at least;  it's not a new idea) worked, then all of Alan Greenspan's attempts to peg the US dollar to the price of scrap steel would have worked.  They didn't work.  They were fundamentally flawed.

   Starting with the idea of value stabilization in relation to a domestic price index associated with the territory of one state, beyond that there is the natural and logical concept of internationally based comparisons. The currencies being compared, like now the euro, the dollar, the yen, the pound, the swiss franc, the swedish kronor, etc., can be viewed with critical eyes by their users and by those who may have the option of whether or not or how to use one of them. This can lead to pressure for good quality and consequently for a lessened inflationary depreciation in value.”

    “It seems possible and not unlikely, however, that if two states evolve towards having currencies or more stable value as measured locally by national CPI indices that then also these distinct currencies would tend to evolve towards more stable comparative relations of value.

    Then the limiting or “asymptotic” result of such an evolutionary trend would be in effect “ideal money” but this as a result achieved without the adoption of anything like an ICPI index as a basis for the standard of value.”