Apart from data, I expect ebay recognise that the forum serves a very useful purpose in a number of ways.  For a start, people can come here and get an answer to a specific problem, which could mean the difference between buying something (thereby adding to ebay’s coffers), or walking away.  So ebay doesn’t have to bother with zillions of pesky people asking questions, they get the forum to do it free of charge.  There is even a benefit to allowing people to complain on here - it keeps it in-house instead of pushing people on to other forums and social media outlets where dissatisfaction can be spread far and wide.  Moreover, I expect most of us regularly click on a poster’s listing, particularly if you intend to reply as it could shed light on the poster’s problem.  All those clicks on the product listings are priceless.