In our area (Colchester), listed status is often seen as an inconvenient obstacle to wealth-generation, so developers won't make any effort to maintain such structures or equipment and happily let it go to rack and ruin, at which point the building has lost its architectural value, planning permission has to be granted for demolition just to clear up the eyesore, and the developers get to make lots of money by building their flats.
It's a long-running theme in Colchester that these properties are often given a helping hand on their road to dereliction with apparently suspicious fires breaking out in buildings where the (admittedly old) electrics would have been disconnected years ago. Daniel Defoe's house (planning permission for nine properties on the site of the Grade II listed building refused) has has two fires in three years - the first one in 2009 almost destroyed it - and every few months a derelict building somewhere in Colchester is destroyed by fire.
The worst example is the closed Severalls Hospital, again listed but of no value to the local health authority until the land it stands on is sold to developers. Only a token effort has been made to maintain the redundant hospital or secure the site perimeter, and since its closure the hospital has been systematically destroyed by vandals, again with fire destroying important parts. It is almost beyond repair now, i.e. at a point where developers can knock it down and start with an empty site instead of converting the existing buildings into homes. An empty site is a far cheaper and more attractive option to them.
I hope Cambridge's listed Richardson Candles aren't so much of an inconvenience that there's a suspicious increase in road traffic accidents