All hail the Peacemakers 21
Netenyahu won the election in part becuase he won the argument for requirements for coalition. Israel has second class voters. It pretends to offer political power to Arab parties while making sure that there would be a taboo on them having any actual "king-making" power.
The Arabs in Israel have seats but have been made untouchable when it comes to coalition building. The accusation against Gantz that he would take power with the Arab partners was so dangerous to Gantz that he declared that he would only work with Zionist Jews.
The refusal of Israelis to accept Arab parties have effectively made it impossible for anything but the right to win.
With this statement, it was no longer possible that Gantz could build a coalition. He either would not be able to offer the numbers or would be working with the Arabs so would be rejected by any partners other than Meretz and Labour.
The reason Netenyahu clings to power is becuase of the exclusion of the democratically elected political representatives of non-Jews in Israel that was promised prior to the voting.