The castle in the photo needs restoration, which is hugely expensive compared to restore a house.

I don’t about Romania, but in other European countries historic buildings are required to be maintained by the owner and it is restricted what they can do.

In Spain if the castle/palace is considered as a good of cultural interest, the restrictions are even higher. You cannot do activities that can damage it, like converting it into an hotel or restaurant. Also required to allow the public to visit it for free, at least four days each month.