А зачем держать эти трамвайные вагоны 15+ лет на открытом воздухе? Почему их не списали?

Судя по обстановке вокруг, их мог выкупить и разместить у себя на участке какой-нибудь транспортный энтузиаст и/или коллекционер. Может быть, хотел восстановить их, но денег не нашлось (или другие обстоятельства).

All the preserved trolleybuses and trams are part of the national cultural heritage, having been saved by an association from scrapping.

All the trams were last restored sometime around 2009-2010 and were used in annual parades. Until a few years ago, all the trams were kept in the Take Ionescu depot (example: https://transphoto.org/photo/466591/) until the hall became an exhibition space for various cultural exhibitions and the trams were abandoned throughout the city.

I don't know if they will ever be restored again and presented to the public. Right now the company's priority should be replacing the entire trolleybus network because it's the most miserable in the country. They bought new trolleybuses that they are currently using as electric buses. The frequencies of the city's transport are pathetic, there's no point in buying new trams, trolleybuses and buses if you have to wait 20 minutes for one.