Some of the reasons:
So many apps created then abandoned
User experience in general is horrible
Public private key confusion
Retarded douche bags fighting with sincere people
Gay porn popping up out of nowhere
Lots of spam
Connecting wallets is not easy
Bad relay management allowing spam, porn, etc.
Diminishing numbers of users
New people are used to algorithms, lack of algorithm provides less interest and energy.
Lack of funding for legit apps that we need like a YouTube alternative, Instagram alternative, etc.
Lack of interest by the masses for real freedom and sovereignty
Many new folks see too much Bitcoin posts and are turned off.
