According to my observations, the Fediverse grows whenever people look for alternative. People do that whenever their comfort is disturbed by material changes. E.g. Reddit gated app APIs, people's apps started shutting down, protest ensued, it failed, people looked for an alternative, many joined Lemmy as the obvious one. That created one of the largest spikes in active usage. There were others following that. There are network effects keeping people where they are unless there's a significant force pushing them to overcome that. And so I think the Fediverse would grow the same way it's grown so far. By being here for people whenever they can't say or read something the way they were previously able to, as corporations enshittify to profit maximize. You even see them doing that themselves, with Bluesky for example, where they built an alternative that pretends to be federated in order to capture refugees. But Bluesky is inevitably going to get fucked too and since it's federated in pretense only, there isn't another instance to take over. I think the process is similar to Linux adoption. It was always there, chugging along for people looking for alternatives. It hasn't stopped growing. It hasn't exploded but we're not complaining about where we are, are we.

Just from a quick look at https://fediverse.observer/, it looks like the Fediverse is mostly steady at 1-1.25 million monthly users (give or take) over the past two years with a slight decreasing trend. I think there are some reasons for this that are not entirely in our control.

There seems to be a global sentiment of disconnecting from social media and the internet in general. So, I wouldn't be surprised if ever platform is seeing a decaying user base. Anecdotally, among the people I see in real life, there is a general sense of exhaustion with online spaces. Whether it's from corporate-own, enshittified platforms to even places on the Fediverse, the people with whom I interact tend to find the entire thing hollow. They've trimmed down to one or two platforms (if that). In fact, I've even started to get that way. In the past, if someone were wrong and arguing against a point I made, I'd engage, especially if it's in something that I have expertise. Now, why bother? There's no use arguing; people have little interest in admitting fault or engaging in good faith (again anecdotally). That said, I'll concede that the Fediverse is a bit better on that front, but not by much.

Then there's the alternative nature of the Fediverse. It's been rehashed over and over about how "difficult" it is to get on and use. It's not actually that hard, but the barrier to entry is an extra step. That small extra step frightens people away from even joining. The only time that barrier gets broken is when a "legacy" social media platform does something anti-user. Then there is a refugee wave that comes in and goes out leading to a modest durable increase in users. Recently, there just hasn't been a major controversy on a major platform that leads people here.

Now, my final thought on this is to ask: Is a small and steady-ish population (despite modest decay) actually bad? In my view, I don't think it is. Being smaller and with a smallish barrier to entry means that we exclude a sizable number of the low-effort population. So, there's less (no zero) slop here. Plus, discussions, when had in good faith, can be much deeper and less filled with stupid low-effort jokes. Overall, I'm not too concerned with the number of people on the Fediverse. Growth isn't necessarily the best thing. Even so, with the way most mainstream platforms are going, it's inevitable that they will do something stupid that drives more people to the Fediverse at least for a time.

TL;DR: The monthly population is mostly steady with a modest decay. Most social media is likely seeing similar trends. I don't think the smaller userbase is that bad of a thing.

Kiwi here, originally European so I get content in two languages and from people with some interests in similar. Good percentage of local and international stuff generally keeps me happy. (Not too concerned/glad about overall numbers - there's no continuous growth on a finite planet)