I think part of this has to do with googles actual customer base: Adwords users. The goal of Adwords is to have every single search be worth the maximum possible value in an advertising sense. So if one person a month searches for "Office desk drawer repairman Concord California" they do not want to service that very detailed long tail search, that would minimize value for themselves and maximize it for the advertiser. They want to treat that search in a vague sense so they can display more ads for their customers and charge for each display and click.