People say these chairs are already paid for and that may or may not be completely true. Some vacation rentals include chair set ups as a part of their package so there are set-ups for people sitting there all week with no intention of being used. I wouldn't have an issue with the chair service if they were set up when the customer arrives and then removed when they leave, but that's not likely ever going to happen.
It is unfair to the tourists and locals to have to compete with empty chairs and professional businessess for a space on our PUBLIC beaches. Vacations should be relaxing and shouldn't require 5am wake-ups to claim a spot on the beach.
In my eyes, a simple fix to much of this issue would be to deny set-ups before 9 or 10am. This would give people plenty of time to "claim their spot" and would mitigate the taking over of 50% of the beach.