Not go out - Because most of the houses in cities were occupied by artificers and traders whose wealth did not consist in lands.
Related Commentaries of Leviticus 25:30
Leviticus 25:30
30 And if it be not redeemed within the space of a full year, then the house that is in the walled city shall be established for ever to him that bought it throughout his generations: it shall not go out in the jubile.