Well, losing users is only the start of it:
From the article:
"U.S. users older than 18 spent 10 percent less time on Facebook in October 2018 than they had in the same month the previous year"
10% YoY engagement drop is seriously bad.
BTW, never created FB account, but as @DangerDave's meme said, it's because I basically hate people. Don't have a need to connect with folks I was in elementary school with, their aunt, or my kid's classmates parents. So, instead of having to be rude and decline rando's 'friend' requests I just decline the whole experience. :-)