It requires something more than foresight - it also requires that the demand for mid-range apartments now matches up with the demand for luxury high-rise apartments several decades ago, and there's simply no reason why this should be so. (Oh, and as timr points out, it also requires that the buildings can't more profitably be refurbished into luxury apartments. Basically, it needs to be grotty enough that the wealthy don't want to live there, but not so derelict that it gets demolished.)