The problem is, in order for Bitcoin to become a currency everyone will use, it should be stable. I know that you might say that people will still use it because it's not about stability, it's about freedom and technology. I agree with that, but Bitcoin needs to be stable in order for people to treat it like money, and not like an asset.
One of the reasons why Bitcoin is not yet stable is because Central Banks and most countries around the world do not yet support Bitcoin as an alternative currency. As you can see what always happens in the Bitcoin market, every time an investor enters the market the graph goes up immediately because it creates a huge wave in the Bitcoin price. If the demand decreases, it will affect the chart and it will drop immediately. The price of Bitcoin will be stable and nothing will affect the market when the market starts to develop which is supported by the state and central bank. imo
Until whenever bitcoin will not be controlled by anyone including the government or central bank, bitcoin will not be stable and will still have volatility, therefore it will still be very difficult to become an alternative currency in all countries, but only a few countries can maintain it because the value of their currency is weak.
Whales can control the price of bitcoins because they have a lot of money already put in there so it is only natural that there are big waves that cause the charts to go up and down, so bitcoin can still be affected by any news that can cause new waves in the market.