Never getting knocked down. It's a thrill ride, it's unique to Disneyland, it was overseen by Walt, it's immensely popular with the GP, it's a Disney mountain and it recently received a refurbishment in 2015 which added new animatronics and screen sections. There are like, zero reasons for it to be torn down for expansion when the lagoon, Autopia and the subs are right there. Maybe if for structural reasons it was a hazard to guests, but that's a problem that can be addressed without demolition.