The Friends likely don't have the knowledge or ability to maintain the facility if serious damage happened.
Infrastructures in the more unforgiving regions such as the bridge and walkway in the tropical forest had decayed and the bus are eroded by rust. Even if assuming the Sand Star would keep any natural disaster from happening, the facilities left by human will be gone one day.
There's only so much the Lucky Beasts could do to keep maintaining the park, and even then many parts are likely need to be sourced from factories outside the island.