This is the key here. There is absolutely nothing to do with heritage, it is - plain and simply - not worth spending the money on tearing something down unless you need that space for something else, OR it's dangerous leaving it as it is.
When Storm Coaster was built, the quoted "cost" of the ride included the costs of demolishing Bermuda. By including the demolition costs in the overall construction, it forms part of the 'new ride' budget, rather than having to find capital works budget elsewhere. It also has potential tax benefits if it was costed as part of new capital infrastructure, as opposed to standalone demolition of end-of-life assets.
There are many benefits to doing it as part of your new project. There are no benefits (other than perhaps aesthetics of the park) to remove it at end of life with no plan on what you're doing with it.
Heritage doesn't even play a part. No question. End of story. Period.