tl;dr: a usecase for non editers.
currently music brainz is only usefull of the nerds who like to do some music research and fill in the data. often helped by some userscripts they contribute by adding the neverending amount of data that still needs to be added.
there is currently no insentive for bands/venues/festivals/… to enter their own data. the only insentive is “preservation”.
while the data could be VERY beneficial for all parties, there currently isn’t a big usecase for them to keep everything updated. and since they’re not doing it, we (the volenteers) have to try add the vast amount of data.
if there would be a user version of music brainz where its more about what artists you like, what venues you like or are close by, some recomendation tools that are based on multiple stuff (similar taste, same band members, support acts for main performers,…) maybe then bands would add their own data. vanues would add their own FULL gig history. we could see FULL artist tours, …
i know that the plan for listenbrainz is to more incorperate a user type site using music brainz data. but this is (currently) only directed at artists. while it would be logical to also add stuff for venues & festivals in there aswel.
i know that a bunch of festivals create a spotify playlist with songs of the bands they booked oon their festival. if they would enter the data in music brainz, this could be automaticly generated. if users could select artists they liked, they could get a personalized playlist to prepare them for their favorite artists on that event.
since the data could be there, the potential could be there. but because the usecase isn’t there, i think it will never be more then it is now. a site full of data that is interesting, but that won’t reach its full potentiol.
and because of that, music brainz probably will not become a household name in the music scene (except for the music nerds).