When this house in Austin’s Hyde Park neighborhood went on the market in 2020, a lot of people assumed that it would be bought and torn down. It had been built 70 years earlier, and it showed its age—the front yard was overgrown, and dirt, or mold, or both, crawled up the exterior board-and-batten siding. The lot was large—almost two-thirds of an acre—so the possibility of subdividing it loomed, and the real estate agent marketed it as a "rare developer opportunity."