one of these old mansions ... you'll be disappointed

It sounded really strange, when the lawyer told the family about the house: "oh, it's one of these old mansions, they used to build 50 years ago ... you will be disappointed". Why on earth should anybody be disappointed about getting an old mansion, especially if you get it as inheritance. Sure, we learn later that the lawyer wanted the family to stay away from the house, so he had a reason to downplay the house. But I remember hearing similar statements in other old movies - statements how nobody supposedly wants to live in an old house. Could that be some mid-20th century thing? Perhaps people really did not appreciate old and large houses back then? Perhaps most people really preferred to live in apartments or freshly-built modern houses? That kind of attitude seems really strange now.