Simply because those entries are not static. When Jane Deer creates a new Blog jane-deer.com, your local database would not know which server to contact to res

Simply because those entries are not static. When Jane Deer creates a new Blog jane-deer.com, your local database would not know which server to contact to resolve it, and nobody is gonna notify the database in your home. So you would have to contact some other kind of database outside your home to find out how to resolve that domain--which you might have already realized sounds a lot like a (non-local) DNS server...