we all know no one can controls the bitcoin price because bitcoin isn't like bank, stock and valas. but if the whales owned 51% of bitcoin, can do it?. if happen, does decentralization not exist?
Decentralization does not mean that a person cannot hold majority of the bitcoins. The difference here is that the bitcoins are limited in number and they supply can't be increased. So in that case if you want to buy bitcoin you need to pay a highlight price and acquire bitcoins.
If there is demand in bitcoin people have to buy it from the market and this is difference from the fiat money where the powerful people can just print the fiat money.