They don't have any reason to drive engagement. Gamefaqs could have a million daily message board users and it wouldn't make them much money. Message boards are dying and are only viable if they're not for profit or are treated as a side benefit attached to something profitable like Steam. Unlike other forms of social media you can't data mine message boards, and owners are liable for toxic users. The hot new thing is killing all your forums and telling everyone to go to Discord, this is what Ubisoft and a few other publishers have done.