Why does it not look likely? 9/11 victims have not gotten a full accounting of the events surrounding 9/11. This new law opens another avenue for them pursue justice in holding the perpetrators accountable.
No I don't believe Saudi Arabia will be cooperative but that is no reason to deny 9/11 victims a chance at closure.
Closure or revenge? Or more like expediency? Or greed? Looks like 9/11 is turning into an extortion game. It is possible that in all court cases, those who always demand "full" accounts are clever and opportunistic extortionists.
In most wars, people count themselves extremely lucky if they get a symbolic compensation for their losses. But there are some that turn to devote their lives to exploit it and join in the robbery. Those 9/11 victims that join such law suits will have to prove in front of the court of international sentiment that they are not in this category.