Let's see how it will play out once Facebook reaches MySpace-style decline and shareholders would need to get as much money out of Facebook as they still will be able to.
Perhaps there is some study to be done where social sites/apps become obsolete if they fail to adapt their UI/UX over the years. I mean look at sites like Fark and SA compared to what is popular nowadays like Snapchat or Reddit.
I'd actually argue hallelujah that reddit hasn't significantly altered their UI. It may not be pretty, but it doesn't take that long to get used to its quirks, and when you do it is extremely fast and easy to navigate and find meaningful content. I contrast this to slashdot, who proceeded to make their UI WORSE with every update (more "modern" styling and response, but they made it totally broke the usability of their commenting system).
Facebook has algorithmic targeting of ads second to none on the planet (most of which happens entirely outside the purview of ad blockers) and pretty unrivaled view of what customers are doing across devices. On top of which they have several other businesses that could one day grow more profitable than FB itself.
We can talk about whether Facebook's model is sustainable, whether demand for behavioral targeting ads will hold up, or if the likes of Instagram and Oculus can ever turn really profitable - but a MySpace style collapse is more or less out of the question.
Instagram, Oculus, WhatsApp – all extremely valuable, not to mention other products like Messenger.
Facebook won, they locked up the market. The match is over, there will be no meaningful direct challenger in the next 10 or 15 years to what Facebook does at its core.
Facebook is Google, MySpace is AltaVista.
In 1999 during the dotcom craze that bolstered Sun, they were generating about $300 million per quarter in profit. Inflation adjusted, Facebook is already four times larger, and they're growing extremely fast.
Sun was more like DEC. They never had anything in common with Facebook's business position today.