The answer to this question is Saad Hariri. As simple as that. In June 2013, 10 months before the end of the term of President Michel Sleiman, the term of the Parliament had ended. The Prime Minister at that time was Najib Miqati. Saad Hariri was in Paris, too scared to join the Lebanese their daily misery. Saad, fearing that if elections were held while he is not in power, Miqati will gain more seats. He refused to take part in the election. Nabih Berri grabbed Saad position and decided that he will not participate in the election without a large Sunnite group, fearing more troubles between Sunnite and Shia.
They extended the term of the Parliament which opened the door for extending the term of President Sleiman. Hizballah and his allies refused to extend the term of Sleiman. If Saad accepted to take part in the parliamentary elections, no one who have suggested extending Sleiman term. We ended up with no parliamentary and presidential elections simply because Saad from Paris was afraid to lose more seats in the parliament. The vacuüm we have today is due to ignorance and street politics of Saad Hariri.