Fb seems like a company that’s past it’s peak. Their brand and public image is garbage and they’re just going to extract as much profits from their dwindling user base as they can on the way down.
User growth is up, even on Facebook alone. If what you say is true you might expect weekly users to be up-or-flat while daily is declining, as people are locked in to the platform but less engaged with it. But daily users are also up.
If they're not removing obvious frauds in these numbers, they'll be the target of shareholder class action lawsuits. In general, numbers published by big corporations tend to be reasonably sourced due to this reason - gotchas tend to more subtle.
Privately held company numbers on the other hand are generally much more suspect (Uber before IPO, Snap before IPO, We work, Theranos...)
But there are plenty of proxy measures that show similar growth. For example the AppAnnie "active user" measure actually measures on device usage, and shows that 4 out of the top 5 most used apps world wide (or maybe ex-China? Unclear) are Facebook-owned (WhatsApp, Facebook, FB Messenger and Instagram. WeChat is number 4).
Even if Facebook is shrinking, I don't think WhatsApp and Instagram are, and who knows what other companies Facebook may be able to buy up rather than be overtaken by.
That is just mind boggling. Literally a third of the entire earth has a Facebook account. Yes, duplicates are a thing if someone remakes an account, but most don’t.
Having tried the oculus quest, I'm quite terrified that FB will rise back as the central VR provider. They've got the best user experience as far as that goes right now, and Zuckerberg has made it clear thats going to be a future focus of the company
Social apps are like clubs, they are hot for a while and then nobody wants to go anymore. Facebook the company can beat that by building new apps (open a new club) and keep reinventing themselves that way. It's not easy because being ahead of social trends consistently is difficult, but they can just buy whoever cracks the flavor of the decade. I suspect in some incarnation or another they will be around for a while.
FB has enough money, tech, lawyers, and infra to dominate whatever business they decide to aim their cannons at. It's not really about facebook dot com anymore. If they wanted to, they could destroy Uber tomorrow. You have to look at it more like a country than a business.