People saw Edith as a symbol, an old woman standing up to developers. Barry said that wasn't it. She didn't stay out of principle.
What Edith wanted was much simpler. Her mother had died in that house, on that couch. Edith wanted to die in the same house, on the same couch.
She did not want to end up in a nursing home. Barry promised her that, on his watch, she wouldn't.