If you really care about improving the wiki, I would suggest submitting an adoption request. It looks like the last edit aside from you and Wikia staff/bots was back in 2016. The founder's last edit was in 2009 and the only other admin's last edit was in 2008. Because of this, staff might bring it up when they contact you about enabling Discussions since you appear to be eligible already. When/if they do or when you submit the request, you may want to ask them to retain the founder's tag on the founder's profile. By default, it is removed when the founder is relieved of their permissions but staff can force it to remain if you ask them to. It doesn't have much benefit but it is helpful in identifying who started the wiki. Also, on the off chance that they come back, they are less likely to feel slighted.
Well, yeah it is old. That is the most probable reason it wouldn't already have Discussions. If it were new, it would have Discussions by default. If it was older than Discussions but not "too old", it probabl would have had Forum. Then, due to activity and small size, the Forum feature would havev been autoconverted to Discussions when Discussions was released.
Ummm... Did you request the wiki to be closed? I am getting the "this wiki is closed" page when I try to go there.