If by "adoption" you mean merchants accepting USD payments from a BITCOIN DUMP though BitPay, or people using BTC as a store of value and losing 70% of its purchasing power in a year, then sure, "adoption".
That's a first, and necessary step: retailer adoption. Of course they have to convert immediately to fiat, as their costs are billed in fiat. This implies fast coin turnover, high velocity, and low bitcoin value.
Once this is generalized, and it becomes second nature to be able to buy stuff in bitcoin from retailers (implying low bitcoin price for this fundamental), then suppliers might be interested in being paid in bitcoin. It may become interesting to receive part of one's salary in bitcoin (as most retailers accept it).
And *that* implies suddenly that not all retailer bills are in fiat. That implies that retailers will not convert systematically all in fiat, because they can spend the coins themselves (in salaries, in bills of their suppliers....).
That will:
1) boost the amount of stuff bought with bitcoin
2) make holding times much longer
and hence imply much higher prices (longer holding times, and larger volumes of traded value).
At that point, if ever, bitcoin will have become a currency. Price will then be determined by the monetary formula.
Bitcoin can also have other fundamentals, such as "store of value" a la gold, but I don't believe in that until people get much more confidence in it.
This is a multi-decade program.
