Flashback from '07 "Don't mind the shirt, it just matches the color of my eyes" (hope I remembered that correctly). Anyone remember what that's from ?? :D
It's from TheSource's signature and refers to his profile picture of himself wearing a shirt with the word 'Wii' written on it. It was tongue in cheek and alluded to accusations of Nintendo bias in his sales analyses.
There are a few important things to note.
1. IIRC, the notable decline started around August 2017 according to Alexa.com traffic numbers for VGC. While it has been mentioned by a few people in this thread that a new console generation will bring in more activity due to things being shaken up, Switch is already happening and has ended the streak of PS4 domination in the weekly hardware charts a long time ago. In 2018 the PS4 was merely winning, now in 2019 Switch is on top. But none of that has generated more traffic.
2. Apparently the site's stability/functionality on mobile devices is still very questionable. On the same note, what happened concurrently to the beginning of the decline was a lot of work on this website that repeatedly led to the site being inaccessible for several hours and at times even longer. Those days are a thing of a past, but how the site runs on mobile devices is something that needs to be looked into and worked on. People aren't going to visit a site regularly when it is a pain to browse the site in question.
3.1. Problematic users create traffic via controversy, so the traffic itself can be interpreted as something positive for the site. However, the negative side is very hard to quantify, because you can't count what isn't visible. Allowing controversy of ridiculous levels usually has the side effect that people who could contribute something of value refrain from posting, because their posts would get buried by the controversial drivel.
3.2. A contributing factor that has not been mentioned yet is that there are a few Discord servers where dozens of VGC users are members. While that isn't a problem at all when the users in question are active on VGC and in Discord, there's a good amount of users who have used Discord to replace VGC. They more or less actively avoid most, if not all, of VGC for what they want to talk about. Partly because the people they want to talk to are also on Discord, partly because of 3.1.
3.3. Of course the direction of moderation matters in this bigger point. When it goes in a direction where, for example, people heavily utilize the official VGC Discord server to say what they think about quickrick because they know that they would be moderated on VGC for merely stating how it is, then something's going wrong. That's the kind of situation where a mod team can drive users off the site. Another example, a more general one, is the direction that there's virtually no limit to how stupid someone's posts can be, so people can behave deliberately obtuse to troll, because a giant exploit is just lying there and waiting for them to be used; meanwhile, there's a bigger risk to get moderated for calling out such behavior. That creates an environment where people who could contribute something of value ask themselves why they should even bother, and subsequently either become inactive or never become an active member in the first place when they are lurkers.
4. Sales numbers going missing is also important. The decision to stop with the software tracking was reasonably explained and I agree that it is fine for two reasons. For one, the rising digital share of software sales lessens the importance of physical software tracking by default, and two, the software estimates have been consistently doubted by an evergrowing part of the community. However, what has been done with the hardware tracking is not good. I have yet to find a place on this site where I can select weekly lists of hardware numbers, like it was done until the end of 2018 where I can select any week of my choice from a dropdown menu. Likewise, I haven't come across any place where I can view cumulative hardware sales for the year of 2019. The "Hardware by Date" tool is just about the only place where hardware numbers from recent months can be browsed, but there should be more than that.
While most of the above points are things that can be worked on, I doubt that the best case scenario goes beyond stabilizing at about the current level of activity. Many of the heavily discussed topics from a good decade ago won't generate much traffic anymore. For example, it has widely settled in on all sides that AAA third party support is not dependent on sales and processing power, because those publishers' behavior over the years has made it clear enough what they'll do. A decade ago there was fear/hope that good Nintendo hardware sales can change where games are going, but nowadays virtually everybody knows which way the wind blows and that that isn't going to change.
Another big example is PlayStation vs. Xbox sales where it has also been clearly established that Xbox is not a brand for global success, so you'll have a hard time finding any Xbox fans who believe that Microsoft can win a console generation. About the only major things that are left are which sales records either Sony or Nintendo can break, or who wins in the USA because the historically high occurence of multiconsole ownership makes things interesting, but otherwise most controversy must be created artificially by making up some arbitrary rules.
Since VGC was and is a site that is built on sales, it's about business, and business is stale once it's understood. Wii succeeding against all odds shook things up in the forum landscape, but Switch succeeding against all odds isn't that special anymore, because Nintendo has done it before. That's the big stuff that this site's staff can't do anything about, so going forward it will be first and foremost about making this website a good place for the people who are still here, because getting VGC back to its previous peak or close to it would be a very unrealistic goal to have.