Facebook clings to dark patterns that surely appear to be "working" in the sense of generating engagement and ad spend.
The problem is, younger users have a much better intuitive sense of those dark patterns because they must develop street smarts about how they can be misused (cyber bullying, revenge porn, deepfakes, etc.)
I don't see how any responsible parent could put a video of his/her kid on Facebook when it's just a simple download away from being turned into someone's perverted deepfake, bullying fodder during junior high, etc.
In fact I'd argue that it's irresponsible stewardship of a child's future online autonomy for a parent to post any pictures or data that could be easily misused/abused by his/her own Facebook network. This means pretty much all pics and videos.
If this sounds silly, consider that Facebook makes deleting pictures one has uploaded a significant chore that requires 10x the number of clicks it ought to.
When I think about deleting some of the old pics I've uploaded to FB that I'd rather take down, the thought of dealing with all the dark pattern speed bumps trying to make it difficult underscores the outright hostility Facebook feels toward its users.
Recently Facebook had a bug where any Instagram account that had been linked to a Facebook account magically got the Facebook user's profile photo. Even this is a crass disregard for user privacy. Instagram is used much, much differently than Facebook and it's completely unreasonable to expect a user to wish to use the same profile photo.
Young people are just a bit more savvy than the rest of us because their peers/foes/etc are more likely to have had the time and inclination to do minor mischief that Exploits Facebook's defaults. Younger users prefer Instagram or Snap largely because the privacy settings are less opaque and fewer dark patterns are used.
This is probably why Facebook bought Instagram, and why Facebook has allowed the younger users to leave... The revenue generated by milking the older users must outweigh the value of having the younger users. After all, Facebook could easily create a linked Facebook account for all Instagram users and role out a new privacy pattern geared at the preferences of younger users if doing so would result in profit.
But as it stands, younger users are happy to engage with Instagram and Whatsapp and Facebook is not throwing away any of the behavioral profiling data, so eventually when the platforms change/evolve Facebook has lost nothing.
Analogously, Facebook isn't wasting time feeling hurt about users not loving its namesake platform. The company is far broader and more encompassing than the namesake app. If you are using a Facebook owned product and generating data in it, you are helping move ad inventory and doing your part to help Facebook make money.