You guys probably miss how cheap oil tankers are vs oil they transport. Even if each and every tanker was hit as badly as the most badly damaged ones, it will still make a lot of money transporting oil. Unless they can not just damage, but sink a very high proportion (say >3%) of tankers, there's no stopping it. But so far not a single one has been sunk out of thousands that transited, they simply have no way of doing so. The longer it continues the more confident the sailors will be is simply shrugging off these attacks.