> Because leaving the friggin' docs online costs so much?
It's not so much about cost but about polluting the Google index with obsolete information. For example, look up a Java API and it's very likely that the first link you will get will point to Java 5. Google is not wrong, that API link is most likely the most linked to, but it's very often not the one you are looking for and certainly not the one that the author of the API wants you to find first.