The game needs something more than just gear characters and collects things. Something else to work on like housing or guild hall.I don*t think its has to do with people leavilng or that some few people think BFA is the worst Expansion ever!!! if you ask me I love BFA and it is on of the greatest expansion I have ever played (I am a vanilla player since 2005)
THe reason why so many guild gets lost is because now days... guild means close to nothing.... there are no Guild housing... every item you can buy in the guild vendor is like any other vendor... the items are not bound to the guild but to you...
and there is close to no consequence when it comes to leaving a guild... since with the sharing system... people never bump into eachothers...
Best things that Could happen,
Make a Guild Garrison/house -
Make the Guild vendor items Bind to the guild... so if you leave a guild and join another one you lose the items...
Make guild give you something cool or some interesting stuff "skills/perks/or something else"
Make it so that when you leave a guild, you get a deebuf of 7 days before you can join another guild... "if you are kicked that does give you a debuf of 4" or something like that.
Open for more ideas that could make guild important again