Some artist's works have an interesting dynamic. One such is Andy Warhol.
A great number of his works were bought by a few families in the USA. These were then used as collateral for loans that underpin empires of real estate & businesses. The value of the collateral can never be allowed to sink, and obviously - if it rises further leverage can be created.
Should a Warhol hit the market it will have a bottom price set by these investors. No matter what it will sell for £300k or £1m or whatever, depending on what category it falls into. If the families have to buy it it will enter the collateral pool, if they don't their collateral remains good, and potentially grows.
So Warhol's, at least are just disconnected from their value as anything but a token. I suspect, very strongly, that at least some of these stocks have been given similar dynamics by their ownership and control structures. That's sort of ok while it lasts, but at some point someone may drop the ball and if they do then the extent of the pretend value will become very apparent very quickly.