If Bitcoin isn't crushed within 18 months, it will be meaningless to measure the price of 1 Bitcoin in worthless government paper.
This seems right.
I will stop worrying about BTC to dollar equivalents when I can get contractors working on my house to accept it and use it or something similar to sign the contract. At the current rate of adoption, that could happen in the next 18 months. If it doesn't, it's likely because something intervened to stop it from going mainstream. Then, we'll be stuck in the $1K-$5K (or lower) doldrums for the foreseeable future.