It is both perplexing and a bit amusing when young people think it smart to videotape their crimes.
I know of one community in my area that listened to the pleas of bikers and built a quarter pipe course.
The community where this happened has a reasonably priced skate park that the bikers could have used - $5/day for nonresidents. Annual fee for residents $10. However, it would not be as "epic" in terms of size as Splish Splash.
The cost of maintaining such parks is steep, and things are constantly in need of maintenance.
Structures used for these activities get damaged very easily, especially if not designed to be used for that use. My neighbors had over $1500 damage to their pool deck from trespassing skateboarders. The damage was due to the excessive wear and tear caused by the activity, not by someone trying to smash things.
The incident at Splish Splash resulted in $20,000 in repair/inspection costs for the owners, if I recall correctly. They had just spent hundreds of thousands resurfacing the slides.