Zoning is often accepted by planners in a rather Churchillian fashion - acknowledged to be the worst land use planning tool out there, except for all the others. And, the older your building stock, the worse zoning gets - the existing assortment of buildings falls further and further behind current sensibilities of how to use land. One commonly recognized manifestation of this is in older residential neighborhoods where not a single house on the block could be rebuilt under current zoning if destroyed in a fire. (This was the case when the ICC lost Stevens House a few years ago. The emotional response was to rebuild it back, exactly as it was - but this would have violated the existing zoning in a dozen or more ways. We eventually sold the lot, for over $400,000, and it currently sits empty.)