The reason for that is that historically a single domain hosted a wide variety of services and users, so there wasn't a single meaningful name to give it, and g

The reason for that is that historically a single domain hosted a wide variety of services and users, so there wasn't a single meaningful name to give it, and giving it a memorable name was important for the users who relied on that name. I don't think there's such a big gap there, either. It's not uncommon for developers to give large, general-purpose applications nondescriptive code names. This actually tends to be useful when trying to distinguish the names that marketing gives a product (which can change) with the names of the applications that back it (which shouldn't).