The network effect also works in reverse. The collapse of a network can happen very quickly. Facebook wasn't just functionally better than Myspace. Myspace experienced two really bad things at once, uncontrolled spam and adding display ads, at the same time, in 2008. It was easy to get users to just lose their daily Myspace habit and replace it with Facebook.
LinkedIn is unlikely to be mismanaged as poorly as Myspace was but there will be openings for competitors. Myspace and Facebook were unique because they were both very interchangable at that point, although Myspace was kind of like the "public" internet while Facebook had already dropped the edu email requirement, it was still heavily skewed college educated at that point.
Also worth pointing out, the edu email addresses requirement for Facebook likely did a lot for keeping their early network clean of bots and spam at a minimum cost. LinkedIn, on the other hand, basically hijacked their user's address books and sent out email impersonating those users, meanwhile ignoring unsubscribe requests and spam complaints. Which certainly sounds like something someone would end up in jail for doing (they did get in trouble for this.)
LinkedIn is unlikely to be mismanaged as poorly as Myspace was but there will be openings for competitors. Myspace and Facebook were unique because they were both very interchangable at that point, although Myspace was kind of like the "public" internet while Facebook had already dropped the edu email requirement, it was still heavily skewed college educated at that point.
Also worth pointing out, the edu email addresses requirement for Facebook likely did a lot for keeping their early network clean of bots and spam at a minimum cost. LinkedIn, on the other hand, basically hijacked their user's address books and sent out email impersonating those users, meanwhile ignoring unsubscribe requests and spam complaints. Which certainly sounds like something someone would end up in jail for doing (they did get in trouble for this.)