Cost is probably the main cause of the grounding of Pink Lady, but I think it's a bit more complexe that just money.
From what I heard (I'm not associated with the association/owners of the plane at all) :
The plane was operated by a dedicated association "Forteresse Toujours Volante" (literaly "Fortress always flying", sadly funny now she's grounded...) but is owned by the museum of the Ferté-Alais airfield or directly the owner of the museum theirself.
During its flying life, the airfield of La Ferté Alais has a too short runway for normal operation of the B-17 and the plane was based at the Paris airport of Orly during a long time, but they lost their hangar a few years before the grounding of the plane. So during a few years the plane had various "homebase" airports.
Considering the guys who maintained and operated the plane since a long, long time are aging (from their own words) and considering the plane deserved a major maintenance and face the financial load of operating the plane, it was decided to ground it for an unknown length period.
The best solution was to bring the plane to the museum airfield: negociation was done to increase the runway operationnal length to allow a landing "at reduced weight". The ferry of the plane was done just before the type rating of the crew expired and the plane spent a few months outside before a new exposition hangar was build. So the plane is not only stored but displayed at the museum.
This link show the "last flight" and landing at the museum. Of course, it's in French but at the end, the feeling of the flying crew and the association members is huge and moving :
https://www.youtube.com/watch?v=6I6mSC5ewuARumours are the "major overhaul" could be done in midterm futur.
So no, the plane will be never to be sold. But of course, I suppose that that a sponsor or donator would be more than welcome.
About the museum, it's an association, created by a familly in 1933 (so it's probably one of oldest warbids collection in the world)
I attempted their airshow and this association is incredible by the number and the wide range of aircraft type. The airfield itself is "the little french Duxford"