It's not a matter of standards and norms, but objective reality. The art has value. It is an asset. It could be sold. To pretend otherwise is an act of deception. They're cooking the books. The question is why are they making fake books? The usual answer is to skim / profit / launder / etc.

In terms of how museums choose to curate their collections, I don't really care. That's their business, not mine. However economics exist whether they want to pay attention to it or not. They have bills. They have labor costs. At some point the lights get cut off.