Before you read further, this post is entirely my opinion.
I've been thinking for a while about this. There have been times when an inactive admin swoops down into the wiki, make deleterious edits, and vanishes into thin air. Just like a deus ex machina.
For these admins the concept of consensus that I've been trying to nurture with currently active admins doesn't occur to them.
This is why I've been proposing revising the admins line-up to remove inactive ones, but it was met with little response, almost like all other admins are inactive at the time.
While I value past contributions of other people, I also feel like we need to have relevance on who we keep as admins. For one, admins are the people others go to to get help with wiki-related stuff. Inactive admins then can't help much with that.
I think a better mechanism to appreciate top-contributing users have already been in place with the levels system implemented by Yhynerson, so there's no more need to confer adminships solely because they "contribute greatly". Perhaps even a differently-coloured user names can be a substitute, though given their inactivity I doubt people would notice.
At any rate, for those who made it to the end of this terse post, do consider my proposal as linked above. Thank you.