To solve the network effect you need something 10x better than what people are jumping ship from. Even if you had a cleaned up version of LinkedIn, it wouldn't be so dramatically better that enough people migrate to reach critical mass.

Because a non-crap product wouldn't be worth $26B. What you perceive as crappiness is the sauce that keeps you coming back.

There absolutely is something better than LinkedIn; it's email and phone contact. But everybody expects you to be on LinkedIn.