Corrosion was unforseen? Costs for restoring obsolete equipment were unexpected? I suppose they didn't forsee how small their piece of a small air display income pie might be either?
Back in the 1950s a good air display could attract an audience of more than 200,000. The Mk 1 Vulcan, along with the Valiant and the Victor prototype, displayed to more than a million people on "Battle of Britain Day" in 1957. Even a small RAF open day at a remote station like Dishforth could attract nearly 20,000 people. Those halcyon days of aviation are long gone...