I've lived in California off and on for 25 years over the last five decades, and travelled to every corner of the state and every location covered in the Soarin' film. I have never been able to hang glide over Yosemite or the Golden Gate Bridge or San Diego Bay, so Soarin' Over California is a real thrill.
That said, it's just one E Ticket attraction in a park that has 30 other attractions including four other E Ticket thrill rides. DCA has more rides than Epcot, and more than Animal Kingdom and Hollywood Studios combined. The two Anaheim parks, Disneyland and DCA, have a wealth of riches when it comes to ride counts, especially the big E Tickets. Thus, you get lower wait times overall for most rides when compared directly to their cousins in WDW parks.
It's not that Soarin' Over California is less popular with audiences in Anaheim, it's that there's also a heck of a lot of other stuff to do in that park.
More Park Ride Capacity = Lower Wait Times