If you have a Good spot where your old house is and someone needs to purchase it because of a community is starting to develop there and you have land and location they will buy it from you to build new.Like any thing else if its in demand its worth something.Just like collectors of coins paintings etc If the location is in demand, great.,
I'm from the Midwood section of Brooklyn my neighborhood is in demand for the Syrian Jewish community,they wanted my house and other also so they started buying up the old houses for good money. The would then renovate the old one or just rip it down to build a new one. This goes on for blocks and blocks. The neighborhood is now starting to look like millionaire row. It is beautiful.