Presumably mobile compatibility was the issue, no? Everybody nowadays wants to do everything on their phone.

Also, didn't vBulletin have a lot of spam and security issues? It's kind of like WordPress in that using it is nice but managing it is hell.

The last vBullitin site I used was hacked and never came back online. The overhead from running forum software in the age of mass automated abuse is just too great. It's really hard to justify the value of a forum that gets hacked, spammed, costs money, etc when Discord is free and works better for most people.