Yes -- but there is probably no business case where that makes sense. Presumably your launch points are San Pedro/Long Beach, Dana Point, or maybe Redondo. In all three cases, if you want to get to Avalon within 15 minutes, you're paying for the helicopter service. If you're okay with taking an hour, you're paying for the existing boat shuttles, which take a whole lot more than 12 people at a pop and you're able to experience the environment -- it is not uncommon to run into pods of dolphins, whales, etc, on the trip over to Avalon.
In theory, you could open up a shuttle service to Avalon from San Diego, or Santa Barbara. Maybe there's enough demand there, but again the 12 person limit makes it probably a money loser. You'd have to charge so much that people would just make the 90-minute drive to Long Beach and shuttle over from there.