Even Universal will only allow one guest per day to fall off Hagrid because they weren’t strapped in.Maybe wild speculation here, but I don’t think the stationary load does any favors when it comes to guest movement. The train waits for them. With the moving load there is the perception of a fixed distance you have to get settled and a visual interruption if you mess up the flow.
I think more moving platforms would make the guests feel they need to be more consistent leading to more consistent dispatch times set by operations. However, we all know they won’t dump someone off the end unbelted.
The limit at Rip, Ride Rocket is 10 per hour, of course.