The value is: everyone is there. So many users are on it due to "soft peer pressure", not because they value a site like Twitter/Facebook specifically. People who want to "push their brand" are also on there because they have to mostly, not out of some special love for the site.
There is no shortage of others who would be able to replace Twitter if it actually went offline in an hour, the hard part for social media ist getting the majority of users.
In other words: why would anyone support Twitter now? After so many years of clearly establishing itself as something you simply use for free and registered on because you "have to".
Twitter is a big mass that has gained a lot of momentum over the years, and at this point it is very hard to change trajectory or the way anyone uses or perceives that site.
Twitter needs those people more than those people need Twitter.