Bitcoin will always be more volatile than fiat currency, because fiat currency has central banks that can intervene and push the price to the opposite direction and negate volatility. And you are right - it's hurting Bitcoin's attractiveness as a payment method to some extent. But Bitcoin could become less volatile, like gold for example, which also doesn't have any central bank. So, hypothetically this problem could disappear in the long run.
Maybe if more countries like El Salvador adopt it they would buy large amounts if the price only goes down a few percents. For me thats the only way, because normal users are not coordinated. Or do you think the mass adoption itself can help?
Perhaps the vision is different depending on whom you ask, but in my humble opinion Bitcoin being a volatile assest, coin or currency is part of its history and essence at this point. I did not meet satoshi but I would assume he/she could not created a crypto-currency both decentralized and stable, so he went for the decentralization (the important characteristic that make Bitcoin special).
He couldnt make bitcoin a stablecoin for obvious reasons but maybe we can see a stabilization from outside of the network later, like from countries or large institutions. This would have the ability to influence the price without compromising the décentralisation. Still this System would need price changes if supply and demand change, which I think is good since bitcoin is not a stable coin. But with large enough sums you could only find a level that is acceptable for the moment like it is done by every central bank with every fiat currency. The only options they would not easliy have is to lower the price by inflating the supply, which could lead to problems.
