Why Bibi?

Bibi's strong, politically, despite years of police inquiries, and reports suggesting that he might be on the edge of a criminal indictment.
Recent polls indicate that he is usually the favorite as Prime Minister in the event of an election.
Bibi's lead over others has never been large, but Israeli voters don't give a majority to anyone. Currently Likud has 30 seats in the 120 seat Knesset. Zionist Union has 24, and eight other parties divide the rest. Some of those parties, like Zionist Union, are actually alliances between smaller parties, which campaign separately.
Labor has gone through a primary where it has turned over its leadership for the sixth time since 2000. All in that party are proclaiming unity, but it's hard to believe that they'll go for long without giving in to the party DNA that favors factional and personal competition.
Netanyahu ranks along with David Ben-Gurion as Israel's longest serving Prime Minister. 
Explanations of Netanyahu's continuity have something to do with his personal skills, and something to do with a continuing tilt toward the right in Israeli politics.
Bibi is as smooth and articulate (in both Hebrew and English) as any prominent politician on the planet. Israelis and Americans interested in one another's politics have no trouble comparing Netanyahu's platform performance to the clumsy boorishness of Donald Trump. The Obama-Netanyahu comparison was a lot closer, but Barack could perform in only one language. 
Bibi is also a skilled manipulator, shunting aside aspiring politicians who seemed to be rising too fast or too high toward his position at the top of Likud.
National traits have at least as much to contribute to the Bibi phenomenon as his personal skills. It's been a long time since the prominent issues of Israeli politics have emphasized the values of socialism or social justice identified with Labor's time at the top from the pre-state period to Menachem Begin's electoral turnover of 1977.
By then Israel was beyond its major wars of 1948, 1967, and 1973. It was arguably the dominant military force in the Middle East. However, the Palestinians or Hezbollah, while never a threat to the country strategically, have been capable of making Israelis concerned about their security above any other issue. A Lebanese war from 1982 until the final pull back in 2000, and another in 2006, plus two Palestinian intifadas and lesser waves of violence in the West Bank and missile attacks from Gaza then Israeli responses have produced an overall quiet. The explanation appears to be the other sides' fear of what the IDF would do yet again. However, there remain almost daily efforts of individuals to kill Jews. They are usually thwarted, often with the killing of the attackers, but they are enough to remind Israelis of their vulnerability. Egypt's problems with something akin to ISIS in the Sinai also have produced a few efforts to attack Israeli cities. And Israel is involved in Syria, seemingly intent on keeping Iran and its Hezbollah allies from establishing a serious presence anywhere close to its border on the Golan.
Israel's economic development has contributed to the lessening concern with social justice. Israel has its poor, Jews as well as Arabs. Overall it ranks second only to the US among wealthy countries in measures of economic gaps between rich and poor. However, much of the country's poverty among Jews is voluntary, made up of large and low-income ultra-Orthodox families. Many of their potential earners disqualify themselves from economic success by schooling that shuns language, science, math, and other useful topics. Fathers may spend their entire life in religious academies. Their families depend on what their wives earn, often as teachers, and welfare payments (that do not allow a comfortable standard of living) engineered by ultra-Orthodox political parties.
Upper income Israelis in high tech are more prominent in media and politics than lower income towns and neighborhoods.
Aside from the ultra-Orthodox, the poor Jews of Israel are likely to be those of Middle Eastern origin, still living in the poor towns and neighborhoods built for their immigrant parents and grandparents in the 1940s and 1950s. While some may think that their "natural" political affiliation would be parties of the left emphasizing a more equal distribution of resources, most of those people have identified with the security and anti-Arab themes created for Likud by Menachem Begin, and continued by Yitzhak Shamir, Ariel Sharon, and Benjamin Netanyahu.
Muslim militias, armies, and gangs are currently engaged in internal bloodshed rather than in anything other than verbal threats against Israel. Reports are that Israeli security personnel are cooperating with several Muslim governments, as well as the security forces of West Bank Palestinians. Israeli security personnel are also preparing for additional confrontations with Hezbollah, Iran, and Gaza, and warning of likely chaos and confrontations with West Bank Palestinians when the inevitable happens and the 82 year old Mahmoud Abbas is no longer heading the Palestine National Authority.
Hostility from overseas non-Muslims adds its bit to Israel's sense of tension, if not actual threat. BDS, campus demonstrations, anti-Israel votes in UNESCO, the UN Human Rights Council, General Assembly and Security Council, plus confrontations with non-Orthodox religious Jews over their rights in Israel provide inputs into Israeli politics, and may strengthen the capacity of Likud's nationalism to protect its share of the electorate. 
Labor, and its allies in Zionist Union, should get at least a temporary boost as the result of a newcomer's primary victory. Avi Gabbay is promising unity, which has been an elusive feature of Labor politicians who share a culture of competition to the point of assisted political suicide. He'll be campaigning against corruption at the peak of Likud, likely to get a boost with every revelation by the police in an overly long investigation of numerous issues. Gabbay is also promising a new and more positive approach to negotiations with the Palestinians. This, however, may depend on flexibility among Palestinians, which may be the weakest of the hopes standing between Labor and the Prime Minister's Office.
The police and prosecutor may remove Bibi from the scene, but something else may have to operate in order to provide Labor or any other party with a greater advantage than Likud on matters of nationalism and security . 
Prediction is somewhere between risky and foolish, but there may be enough in the spirit of Menachem Begin through Benjamin Netanyahu to keep Likud on top.
Comments welcome
Ira Sharkansky (Emeritus)
Department of Political Science
Hebrew University of Jerusalem