You're reading it very wrong.The way this looks is that, the other parties are splitting it enough that they can't get rid of him. In fact its interesting that his seats increased, presumably many coming from those lost seats some of which are right wing.
The left wing of Israel should take note of this. They need to find out where they differ, compromise and merge.
Even if you put the Zionist Union as left wing (and you kinda shouldn't, like, they had no problem doing shit like what is talked about in this thread) the left wing block cannot dream to reach 60 MPs.
The problem is not splitting of the votes, its that the electorate in Israel is really right wing.