I've said some of this before in chat and I think it's worth expanding on in a more permanent place. I believe the main contributor to the decline in this site's activity over the last several years is the rise in strong alternatives, particularly game wikis, Discord servers, and subreddits.
Game wikis satisfy this site's mission of being a repository of knowledge about a game, without needing to go through the ask a question/wait for an answer process to populate it. In addition, a wiki often has complete information, which makes them a better first stop when looking for general knowledge, and they are often more consistently searchable. For example, if you are looking for information about a particular item in a game, this site might have it if someone else happens to have asked about it before, and you can probably find it if you search right. But if you know that the wiki has all of the information about every item, then you know for sure that you can find what you are looking for by going there.
Discord is on the other end of the spectrum. It's a terrible long-term information repository, and it can't be easily searched, but you can often go there to get a personal answer to your specific question very quickly. Many game Discord servers have a continuously ongoing conversation among whoever is online, so if you pop in and ask a question, you know people will see it immediately. In addition, many game Discord servers often have devs actively online, which gives you an opportunity to get authoritative information that can be hard to get elsewhere.
Game subreddits occupy somewhat of a middle ground. The search is not great, and questions don't get answered quickly, but questions do often get answered, and a lot of games have a lot of active discussion. You can often learn quite a bit of information about a game just from reading the discussions other people have about it.
What all three of these things have in common is that they are all communities for individual games. If you're a fan of a particular game and you want to engage with a community, you will find more people who share your particular interest in a community specifically for that game than in a community for gaming in general. I think all of that leaves this site in the awkward position of not having a lot to offer its target audience that they can't get more easily elsewhere, as a simple result of the nature of the site.