Then how it's possible Mossad didn't know about what had happened on 7 October 2023?
(Portions of the US intelligence apparatus knew, but that knowledge didn't transition into action)
It's one of the many asymmetries that changes when you are the defender versus the attacker. As the defender, you have to be right 100% of the time. As the attacker, you have the luxury of being right only 30% of the time. The law of large numbers is on the side of the attacker. This applies to missile offense/defense and to usage of intelligence.
This information asymmetry is also one of the key drivers of the security dilemma, which in turn causes arms races and conflict. The defender knows they can't be perfect all the time, so they have an incentive to preemptively attack if the probability of future problems based on their assessment of current information is high enough.
In the case of Gaza there was also an assessment that Hamas were deterred, which were the tinted glasses through which signals were assessed. Israel also assumed a certain shape of an attack, and the minimal mobilisation of Hamas did not fit that expected template. So the intelligence failure was also a failure in security doctrine and institutional culture. The following principles need to be reinforced: (i) don't assume the best, (ii) don't expect rationality and assume a rival is deterred even if they should be, (iii) intention causes action, believe a rival when they say they want to do X instead of projecting your own worldview onto them, (iv) don't become fixated on a particular scenario, keep the distribution (scenario analyses) broad
An example of this is France cutting off all support after Israel's initiation of the Six Day War, which followed signals such as Egypt massing troops on the border. The problem for Israel was the lack of strategic depth combined with the geographical low ground, which creates these hair trigger scenarios with no room for error, reducing the threshold to act preemptively. The more abstract problem was the absence of a hegemon in the late 20th century that had security control over West Asia, which is a necessary and sufficient condition for resolving the security dilemma.
Interesting number you suggested. That's a pretty normal success rate for a carnivore attacking prey.
And asking how did they miss something is like asking how come AWS has downtime. But I'm sure you could come to this conclusion on your own if you didn't really want the answer to be something else.
b. The Mossad is the equivalent of the CIA, they are not meant to act inside Israel
For that purpose is Gaza inside or not inside Israel?