Overall I'd say one of the biggest reasons is the fact that all their friends are still on Web v2 and Hive has an image of an exclusive club which they need to break into.
The lack of direct message does not help. As a social media to have to tell people to go to Discord for socialising seems silly. Luckily I heard this is being worked on because As it stands it feels that Hive is more like a bulletin board.
I also think the reward pool distribution still needs improvement although I do see it going in the right direction.
I still believe it is early days and if we continue building it, eventually they will come on stay.