I know there are many questions daily, but as someone with the privilege of having access to review queues, this seems concerning. The review queues, whenever I check them, are always completely empty. Either Chess SE has very good quality questions, or the site is going inactive. Is Chess SE going inactive?
I would argue that the site is actually more active than it usually is. I have seen more questions asked for the past couple of weeks than I have seen an average (although the exact numbers may be subject to revision, as I am relying on memory here.) Heck, we had 5 questions on Sept. 25! That’s a lot for us by our standards!
I don’t think that the fact that you have seen few reviews can be used as definitive proof of the site being inactive. For one, any review that there is gets snapped up very soon. Secondly, registered users with a few hundred reputation or so and higher are the ones asking most of the questions, and they know how to make a high quality posts. That overall rules out most review sections from even having a review. And with a vast pool of active editors such as I, users with 2k+ rep, suggested edits are less likely to appear (that and we are a smaller site.) It may also well be a slow income of new users currently, further restricting seen reviews. Finally, we do have EXTREMELY active mods (I spy a Brian Towers edit here, there, and everywhere!).
I welcome others to chime in with their thoughts and reasoning.
I can provide some information with SEDE queries.
Is Chess SE going inactive?
Not likely. If you look at the average number of questions per day, it's between 2 and 2.5, and (with some exceptions) it has been that for a long time:
The review queues, whenever I check them, are always completely empty.
This SEDE query indicates how many review tasks of each type are created each day. First Posts is our largest queue, but it only requires a single review. I see 10 different reviewers in the last six weeks, which I'm really happy about; together we share the load and keep the site healthy.