why are so many mybb themes locked

how come a lot of mybb themes are locked?

cause of thread being closed due to it being old or has too many replies
admin should modify the hide feature to be unlockable on closed threads... though the hide paywall is unlockable via credits there is no reason to have it locked forever

To avoid from your MYBB to get bugged. Only use the updated version, to avoid bugs in future and also to avoid backdoors.

prob cuz they are no longer working or file is down