The study that came up with the breakwater plan was commissioned after the record setting mid-2000's storm laced summers that did move much of the visible beach sand out to sea. This made the beach very narrow to non-existent in parts. For the stakeholders of Negril this was an important issue.
Since then, the summer Atlantic weather patterns have returned to their "usual" normal and that has allowed the beach to un-erode (accretion). As you state, Nature gives and Nature takes away.
