I think this is about a girl who was tired of people wanting her to conform to their ideas of how she should be. Maybe she was an activist sort and built a foundation for some kind of change, and when she got tired of life and left the town, that foundation collapsed and there was no more progress made on that front ("And the house that a girl called johnny built is now just ashes and sand"). This is just speculating, but it's not hard to imagine a scenario like that for these lyrics.
I think this is about a girl who was tired of people wanting her to conform to their ideas of how she should be. Maybe she was an activist sort and built a foundation for some kind of change, and when she got tired of life and left the town, that foundation collapsed and there was no more progress made on that front ("And the house that a girl called johnny built is now just ashes and sand"). This is just speculating, but it's not hard to imagine a scenario like that for these lyrics.