I had a quote of 7000 british pounds to get a negative made from an IB print.
There are a few places that will do it, but that was the cheapest I had found.
It is still the case that when a cinema has oultasted its license to project a film that the print is often destroyed. There is a beautiful IB print of apocalypse now sitting at a cinema in QLD Australia, and their license to show it has run out, and the film company has asked them to destroy the print.