Comment by esperent
It's because everyone moved over to using Whatsapp groups instead, for the actual social stuff, and TikTok, Instagram, and YouTube for the gratuitous lusting after other people's perfect lives stuff. It used to be that we looked at the perfect shared moments from our friends lives, but this didn't make us feel bad enough so we outsourced it to models backed by teams of experts so that we can compare ourselves to impossible highs and thusly feel only the most exquisite of lows when comparing our own real and therefore often shitty lives.
This is the right answer, and it's something I believe Meta has also said publicly, that messaging apps have become the family and friends connection machine as people shifted to using mobile phones and messaging became free and able to handle multimedia.