I know that the airframes have to be maintained and constantly inspected, but is the real cost of keeping her flying those Olympus engines?
There is no support for the engines from Rolls Royce other than the requirements of routine maintenance AIUI. Once the engines they have are out of hours that will be the end of it.
I reckon the only way to keep aircraft of this complexity flying in retirement is to have a major sponsor in that field use it for advertising
In view of its' only role in active combat maybe Fray Bentos or Hormel foods?

In seriousness, it will be a real problem for every historic aircraft of this era and beyond.
Firstly, because the engineering has gone beyond what can be supported by a dedicated team of craftsmen plus a little professional support.
Anyone who can rebuild an engine for a Cessna can do the same on a Merlin engine and keep a Spitfire in the air. Parts are around and, even where they aren't, it's not beyond the capabilities of a team of enthusiasts to get a new piston cast, or get other parts machined, etc.
It's a totally different ball game with a much more complex aircraft like the Vulcan. Materials and techniques used were state of the art and rare at the time, never went into common use and are now obsolete and unsupportable.
Secondly, quite apart from the correct functioning of the aircraft we have the paperwork required to make it fly.
European airworthiness requirements now call on an aircraft to receive "type support" from the manufacturer or a competent body able to fully support the aircraft in operation.
For a relatively simple aircraft one could set oneself up as such a body. The complexity behind being able to tick that box for a complex aircraft along with the potential liabilities if something goes pear shaped are enormous. I bet Airbus breathed a sigh of relief when the last Concorde touched down and they could tear up that particular bit of paper! They won't be persuaded to dig it out of the wastepaper basket for anyone, believe me, and without that, it doesn't fly.
So, there are huge hurdles to clear to achieve a project like this. Credit to the TVOC for finding sufficient loopholes and pledges to manage it with this aircraft, for now, but I'll be very surprised if many more types follow it into preservation other than as a museum piece.

Kevin