In fact, the only truly useful thing it provides is Whatsapp (which it acquired primarily to gain users); and there are good alternatives to Whatsapp, so it's an "also".
The actual human connection features of Facebook turned out to be a novelty as humans discovered that they don't really do enough interesting things often; so keeping up with one's friends doesn't require a live feed, but rather a weekly or monthly note will do.
So once the friend status stuff became so blasé, and users were spending less attention on FB, FB amped up the suggested content. Now, as has been illustrated on some HN posts, the vast majority of what one sees on FB is just suggested content.
Instagram is the same. People just aren't interesting enough to keep an entire platform alive. Sure, the influencers and posers will provide a lot of content, but within any given category there are hundreds of similar (and quickly boring) options.
The grand business model of attracting people to a platform and then showing them lots of ads just cannot survive long term without real content; and there's less and less real content each year.
Meta is so large and has so much marketshare already that no pivot could save them. Their only chance is to merge with a content company like Netflix (where the content machine is arguably already oversaturating the channels and leaving viewers bored despite many new series each year).
In 10 years, Meta is likely to be just another AOL.