Did they just make some mistake/mistakes that led to this, or is it more of a natural decline, with users going to other platforms or quiting social media platforms altogether?
Do you think other social media platforms will experience this decline as well soon or is it more of a facebook only privilege?
Churn (loss of existing users) is normal, and happens all the time to all online platforms. To keep growing overall, any platform needs to acquire more new users than they are loosing old ones in the same time-span.
Facebook has always been loosing large numbers of users - but they've also been acquiring even larger number of users at the same time. In western countries their losses already were larger than their new acquisitions for a while - but they were able to make up for that, by tapping into new markets on other continents.
Also young people are generally unlikely to sign up to the same network that their parents are active in. At a certain age, you just don't think it's cool to have your mom or dad read your postings.
Facebook is running out of new markets to tap into, and is also increasingly surrounded by ever more image damaging controversies. Thus they finally reached the point, where their user churn is higher than their new acquisitions.
All those different factors that play into this - and none of those factors are unique to Facebook. That exact combination of factors might be, though. Most competitors still have new user segments they can expand into, for example.
There is no such thing as infinite growth. You can't just get bigger forever.
Natural generational decline, and it is basically one generational tyrant (TikTok) dethroning another (Facebook). Same thing happened with MySpace.
> Do you think other social media platforms will experience this decline as well soon or is it more of a facebook only privilege?
Every single social media platform will experience a decline of users, especially through new generations. It is not exclusive to Facebook. That's why they are focusing on Instagram instead. Sooner or later Instagram will 'decline' in users. Then on to the next.
Either way, the creators always lose as the platform either goes on the public markets or the small creators start to lose money to corporate users / businesses jumping on the platform.
As Facebook is getting larger and larger, it gets harder and harder for them to grow users/revenue/time on site. So they start adjusting some things so they keep growing. But these things also make Facebook less compelling for existing users, which leads to eventual attrition.