When we went scuba diving and swimming the consequences of their auto-dredging/sand spraying contraption were horrific, extensive and obvious to all. The organised diving trip to the local reef was to a mainly dead, slime covered reef.
Talking with the locals, who were the maintenance and wait staff, made it plain we'd chosen the "wrong" island for experiencing the Maldives.
It was that holiday and the stupidity we saw that significantly changed our environmental awareness and views.
Also, how do they clean the beaches where automobiles are not allowed? Part of Ocean Shores beach doesn't allow cars. And what about the miles of sand dunes, rocky beaches, jettys and other places cars can't go? How do so few people keep clean so much coastline? Are they training seagulls and deer to pick up litter? It doesn't scale...
This. People don't realize how costly can be to maintain a beach in a good state.
I remember getting early to the beach seeing one of this https://gfycat.com/gifs/detail/BronzeOldfashionedKarakul
Even more expensive is beach nourishment https://en.wikipedia.org/wiki/Beach_nourishment
Cleaning work is ungrateful because people only notice it when you do a bad job.