Privacy is a necessary feature in my opinion, but why hasn't Monero become a main coin?
Not all investors will value the term privacy when dealing with crypto as the purpose of creating monero is to promote anonymity, investors still go for coins with higher profit and zero privacy as seen in most cases, Monero is also preferable by most people who value their privacy. I think the choice depends on every investor and this is not just a forceful opinion to hold Monero but rather it has to do choice, I still think the reason why most people don't value Monero is due to the private nature.