There is indeed a backlog, and the CM team is slowly but steadily working its way through it.
The reason why elections take so long to set up is because we need to reach out to the current team, assess their needs, make sure everyone has their say, and only after that schedule the election. Sometimes a mod (or we) will post an interest check post to assess whether there'd be enough interest or not, and whether an election is likely to fail. Sometimes the current mod team will take a week or more to respond too — understandable, since they have their own stuff to deal with, in addition to their moderation duties. And for the 29 sites that have lost their "beta" label last year, it's even trickier to schedule an election without first making sure the whole team is on the same page, because we can choose to trigger their first "full" election (for which we need to make sure the mods are aware of everything it entails, otherwise we're effectively "kicking them out") or to run another provisional pro-tem election (if there's not enough community interest to schedule a full one, for instance) — this because when we removed the "beta" label we didn't mean for that to potentially put these sites at a greater risk of being shut down if a "graduation" election fails.
That being said... since the beginning of 2020, we've concluded 13 elections, have 5 currently underway, and another 3 scheduled. In addition to that, we're actively in contact with another 8 moderation teams to try to get them an election scheduled too.
There's at least 15 other sites with less than 3 moderators, and we've been prioritizing those (unless a site specifically requests an election). Additionally, there's 19 other sites that currently have 3 or more moderators, but who've lost one or more since late last year. This group of 34 is our top priority, but then there are still 20~30 sites that we need to check in on because some moderators are absentee.
Finally, I post the current election schedule in The Teachers' Lounge for mods every Friday... which I know doesn't do much in terms of the broader community being aware of the current and upcoming elections — but you can refer to this tool built by moderator, Pro-tem Mod Council and community member ArtOfCode, which should allow you to see all current and upcoming elections, as well as some extra stats on the candidates.