I'd also like to point out that Israel obviously knew about the drone because they shot it down. So it clearly didn't escape detection.

Additionally, being able to sneak something past lines of defense during peace time is nothing like trying to do it during war. A single small blip on a radar (particularly an intermittent one as might be seen from a stealth aircraft, and which looks like a bird on radar) doesn't often result in the same response during peace time as it does during a hot war. There aren't hundreds of ground spotters on station 24 hours a day. There aren't as many radar systems operating.

A good example would be the chinese sub that infiltrated its way inside the AO of a US carrier group. It likely did this by just getting in front of the carrier group and sitting. During war carrier groups make many angles to prevent such things. The best sonars are not often used during peace time because they drive whales mad. Sona boueys are not dropped all over the place in peace time except during training.

The odds of that same sub doing the same thing during war time are vastly diminished.

The notion of Iran putting hundreds of speed boats to sea, sailing them 300+ miles out and wiping out a carrier group is just absurd. It is not absurd to think that Iran might get lucky and get a boat past defenses once or twice and actually launch a missile or two. Then those missiles might get past air defenses and hit a target. If Iran does pull that off once or twice it won't change anything. A couple of ships might have to be towed in for repair. I don't recall the damaging or sinking of a US ship ever resulting in the US giving up. Not even when carriers have been sank.