Any sane rent vs. buy calculation is going to include maintenance, i.e. battling entropy to make sure that doesn't happen. More to the point I don't think many

Any sane rent vs. buy calculation is going to include maintenance, i.e. battling entropy to make sure that doesn't happen. More to the point I don't think many houses have reached that point. In my casual observation new construction tends to be either not single family homes (different economics) or on undeveloped land. Teardowns are relatively rare in old neighborhoods (though additions and renovations are quite common).