If bitcoin had a stable price it would be popular. Even if the price is stable or not the popularity of this bitcoin is not too much popular. Because many people dont know what is bitcoin. Many people dont need to use it. Many people dont have care about bitcoin. However it is not too much popular right now in the future i think this is the most popular coin even if the coin is not stable price.
To be honest I do not think that Bitcoin would be as popular because most people use it as an investment first because then they can make money.
If that was not the case and you can only use it as an investment not many people would use it.