I would point out that all forum based websites are in great decline as a "species."
I do not believe the trend here is specific to this site or the topic, but to the format in general.
As well the expansion of who is online in the last 15 years has significantly altered the statistical probabilities of who you may run into and what behaviors we may find common/uncommon. That is very easy to observe for online gamers of the period. 64 player games would regularly have a player you would need to mute because they were just going to attention [censored] troll with an endless barrage of racist/sexists/homophobic screaming. Now you don't even bother to join VoIP chat with just 6 players on your team, cause there are always low life yahoos and children and being children. The odds are you can not escape that online wherever you go.
Also the segmentation of a growing internet has to happen. Someone was first to X topic website, but that don't mean they wind up being the only one or even the best or longest lasting one.
And with the division in the world of who could even be talking about care of what ants, in what language? Of course it is inevitable that the world wide population of people into ants will divvy up a bit based on where in the world they are, for what ants they could even be swapping notes about, on top of the division of language favored by what people in what local area.
Like that netflix must loose a huge portion of its subscribers, once there is a more robust market with actual choice on it to be had. When you were the only game in town of course you had all the business, but then once there was viable competition you must consign
yourself to only a share of that now competitive market. And that shift is going to be the biggest looking loss, cause had there been a compeditive set of options, they never could have gotten that big in the first place.
But i do believe more than anything, it is change in format. People use other mediums, and forum sites that just demand more reading or more effort to show off pretty pictures, that too few come see and prasie anyway, means people migrate to other formats.
Oh and a note on the realty of people. It is quite irrational to belly ache on repeated questions. No one wants to go read the encyclopedia, even though the answer to your question is probably in there somewhere. Typical is X, and belly aching about what is typical to face in a way to suggest it's a problem to do something about seems to miss the reality of us humans.
Video gamers know, all noobs ask the same questions. A community that is willing to politely answer them every time is the one that grows when they join the community that was open and helpful to them.
And communities just do have to accept that the hit rate is not too high. Plenty get but never give back, and any community that expects to last has to be ready to accept this and take the 1 new producing member they get for every 20+ they took the effort to open the door for.
If you can't keep treating every noob like you want to answer the questions(for the millionth time), then you are simply not the best ambassador to your group.
Group member attrition is normal and inevitable, so new member induction must at least meet that if not out pace it. Always keeping the door open for noobs is a requirement for any group that expects to last.
Though there is nothing that can be done if the environment has simply changed and the format is what's different.
And still as best as i can tell for an english speaker this is the busiest website online for the topic. Otherwise as has been pointed out, lot of peeps into using discord these days for their online communities.
i do believe that 50%+ of all internet wharbelgarhbels would vanish overnight, if we could just know the objective reality of the age of everyone when we were online(everywhere all the time). When an adult knows it is a kid, they can easily ignore them and the problems of having a mixed social environment of adults and kids would more easily work themselves out, just as in IRL when an adult objectively knows it is a kid they are dealing with.