Good luck with that enforcing hotels to clean the beach (as well as the new proposed anti-teteo drinking laws, moto vest laws, etc)Exactly. Once the law exist, no company can contest when authorities levy a fee on them for breaking it. As of right now, a resort is penalized for not cleaning the beach and they can contest it in court. As of right now, the government can't expropriate their properties due to a dirty beach either.
Any expat that enters as a tourist and overstays the 30-days allowed knows how well penalty fees are imposed.
For the same reason private homes and businesses in New York are forced to keep clean the sidewalks in front of them everytime it snows, ice, etc. Anyone slips on the ice in the sidewalk, falls and break a hip, and you are the most likely culprit to be sued despite the sidewalk belongs to the government.
If it makes economic sense, I suspect like some do, others will clean it up.