This happens only because each year newcomers pay 10 times more to buy bitcoins from those, who bought them 10 times cheaper last year. This will not happen forever. When inflow of newcomers into the system will stop, the game will be over. This happens with all financial pyramids sooner or later.
Why would the inflow of newcomers stop, in any foreseeable future? Bitcoin has obvious advantages over fiat, its march can easily continue for as long as there is fiat currency left in the world.
You know, the number of people on the Earth is finite. And the number of anarcho-libertarians is even more finite.
Right now, capitalization of bitcoins is $1B. If it continues to appreciate 10 times per year, its capitalization would reach $1T in 3 years. To reach this number, every single person in developed world would need to invest $1K into bitcoins. An this is not going to happen, because 99.9% of people do not even know about bitcoins. And there are altcoins popping up every week.
Bitcoin market is going to reach saturation in couple of years maximum. And after that, depreciation in value is unavoidable, since millions of hoarders will want to sell their btc at same rate as they do now, because they need to pay their bills in fiat, but no newcomers will want to buy this btc at this rate anymore.