I really don't think people really care about ease of use and adoption/features anymore, hell just look at Bitcoin, even though it's fee's are totally out of this flipping world and it takes sometime days to get a transaction through, it's so bad even the dark web drug dealers switched to other currencies. Who really wants to pay $25 to send $100 but it doesn't seem to hurt it's popularity does it?
hmmmm, I think you're exaggerating a good chunk here
bitcoin is the juggernaut coin and all mighty godfather. it's mainstream and widely used, other coins are not as fortunate and need to be brought into the spotlight by innovation, community and technology.
i can't say much about dark web dealers but I do understand why they may prefer monero but that's a small small percent of the now emerging crypto markets