The popularity and acceptability of a coin is considered not by everyone having to like Bitcoin but by having two categories of Bitcoin Likers and Bitcoin Dislikes. But Bitcoin is an unpopular currency for those who like banks and fiat but those who like Bitcoin don't like banks and fiat.
Am trying to get the logic behind what you said, although you are right to an extent but there is something we really need to know and thats information, many people may not have a good information about Bitcoin and this might be the reason for their nonchalant attitude towards Bitcoin investment, people do say another man food is another man poison but the truth is that if you have not have a taste of a particular food, you won't know whether the food is nice or not, Bitcoin may be unpopular to those who like banks or fiat as you said because of either lack of information or misinformation about Bitcoin investment, I don't think that an individual that's very much informed about a long-term profitable investment like bitcoin will want to keep his or her money idle in a financial institution without good return instead of using the same money to build a good portfolio in bitcoin investment, I have come to understand that our choice of investment are been triggered by our mentality and exposure.