TGO does indeed have three mods. However, moderation and the number of ♦'s taking care of a site is all about scale. TGO has very experienced moderators (as evidenced by moderating other sites) and TGO is also a very low-traffic Stack Exchange, so it realistically requires much less of our time/effort than some of the other sites.
Secondly, the site is doing very well via community moderation at this time. We haven't had a high flag volume due to things being handled by the community, from edits being approved to post deletions, etc.
The other consideration that is often forgotten is that the community sometimes expects moderators to be the primary or even sole custodians of the site. It's not the moderator's job to answer or even monitor all of the meta posts - I understand that mods (like myself) should be on Meta more frequently, but Meta is about community discussion, not necessarily one asking questions and mods answering or even setting "policy" - rather Meta is a safe space for the community to discuss and come to a consensus on various issues, like if we need another diamond.
Personally, I think TGO doing well with the current staff. I wish there was more discussion on this question than just us three ♦'s, the OP, and one other community member, that doesn't display broad meta involvement across the board.