Their homes weren’t high enough on land to receive the radio signal from the island.
And, sadly, that puts a dampener on Regan’s plans for defeating all the monsters.
IfA Quiet Place Part IIIhappens, that story will likely be about taking the fight to the monsters.
In that case, the island won’t need to be a sanctuary anymore.
Next:A Quiet Place 2 Ending & Future Explained