Privacy is a necessary feature in my opinion, but why hasn't Monero become a main coin?
Monero is genius, it does everything you require from a privacy coin. Unfortunately its strengths have led to its downfall in the hopes of becoming a main coin. Governments hate it & regulators have threatened exchanges with operating bans in their jurisdictions if they list XMR. That has meant exchanges have delisted XMR & that’s the reason why the price isn’t as high as it should be.
It’s a great coin for anonymity but it will never be a main coin sadly.
It's because it's a privacy coin, so what do you expect? But is it true that Monero is hoping to be a main coin? But good for it that it didn't succeed because for us, Bitcoin is still the best even though it isn't fully private and besides there are still a Bitcoin mixer now that can make it more anonymous. But like Monero, governments also hate mixers so they are also hunting them down one by one.
Monero is lucky that some exchange still lists it and it still have some value left @OP, you are wrong. Monero is actually a popular crypto even up to now. It's one of the oldest and the best before but like what @deathangel said here, the coin is slowly deteriorating.