From what I've heard, the tooling was aluminum, so easily damaged and difficult to repair. Plus the aluminum molds from what I was told by another manufacturer at NSE is that they occasionally grow legs and end up being sold for scrap
I think all of KK's tooling was aluminum. So yes, some places won't run aluminum tooling at all. But the other part of the ex-FVM stuff was all the factory parts that were common, and not owned by FVM to transfer to a new owner. Think about standard screws, or bushings, or whatever. All that would have to be recut... or... the path Scale Trains took was to retool within their ecosystem instead.