No, that's not what I meant. If the land to build on is on across a budgetary border, then building stops being a solution even if there's demand, because the b

No, that's not what I meant. If the land to build on is on across a budgetary border, then building stops being a solution even if there's demand, because the budget it relieves is someone else's budget. If most suburbs are in political entities that have land on which to build, then building relieves the budget for another while.