The Israeli intel didn’t “miss” it but underestimated the scale and the risk of the attacks. Imo, intel factions inside the gov’t. allowed it to sow terror incidents to facilitate removing Netanyahu and protect the judiciary.
Another theory is that Netanyahu allowed this, because he thought it would unite the nation behind him (as often happens in war), and allow him to take out Gaza.
But who really knows what the world's various deep states and intel communities are up to?
That's my guess. Israel had relative peace for 20 years since the last Intifada. So they got sloppy.