The whole idea of bitcoin is to be decentralize, but you have enough amount of bitcoins the price can easily be controlled.
It took me 5 minutes of reading before getting to your sounds-right point. I don't think we can decentralize bitcoin's price in a few words. Even in trillion dollar-worth markets such as stock or gold market, organizations still can use money to manipulate stock's price or gold's price. If cryptocurrency's market cap reaches the same level, I think bitcoin's price maybe less manipulated somehow.