Yes and no - depending on how strictly you want to define "like Facebook".
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.
