That's a really difficult question, Tunesmith. For one thing, there's no clear boundary in my mind between names that are and are not descriptive. "The Clash", for example, would give a pretty good indication that they are not going to fit easily into mainstream music well before you had heard them. "Steeleye Span" is an interesting example, as it can be a completely abstract label, or a clear indication that they are folk-related, depending on whether you know the song "Horkstow Grange".

My guess is historically groups didn't have names at all, they would be referered to either "Lord X's musicians", based on their sponsor, or "John's band", where John is a prominent member, or else the "Nearby Village Band" based on locality. In each case, it isn't really a band name, is a description that happened to be handy at the moment it was used, not a permanent name.

Permanent names become relevant when the group needs an existance that is separate from its members, and I would guess these would originate in the big churches and universities: "The King's College Choir", and so forth. A big increase in this would happen when recorded music became available. These seem to be predominantly location and chief-member based, until at least the thirties. I would put a name like "the Squadonaires" in the same class, given it is airforce based. The earliest I know of that begins to be more abstract is "The Ink Spots" in 1932.