FWIW, I asked Simon Smith (the music engraver) about this, and he indicated that it is really a “stylistic choice”, but that Boosey & Hawkes uses “Horn (F)” in concert pitch scores and “Horn in F” in transposing scores.
For me, again, its about clarity- not archaic correctness. Many scores do not have instrument lists. I need to know, whether a score is at concert pitch or transposed, which specific instrument is meant. If a concert score simply says “trumpet” or “clarinet”, and I want to check notation, it’s kind of important to know if I need to do the transposition for a Bb clarinet, Eb clarinet, or clarinet in A. The fact that a concert score simply says “clarinet”- especially absent an instrument list- is not very helpful for that. I also have never been taught to understand that ‘clarinet in Bb’ on a staff label means that that staff is transposed to Bb; Bb clarinet is simply the name of a specific clarinet.
I also have never been taught to understand that ‘clarinet in Bb’ on a staff label means that that staff is transposed to Bb; Bb clarinet is simply the name of a specific clarinet.
I’ve never had that understanding either, but apparently some people do have that understanding, which is why it is a thing.
I do agree you absolutely need to know whether a clarinet is a Bb or Eb clarinet and things like that, and so you would need a parenthetical key for the clarinet at least, ex: “Clarinet (Bb)”.
Interesting discussion, let me show you how some transposing instruments are indicated by Carus Publishing House.
You will notice that both the key of the instrument are indicated, as a result of this, the ancient key with which the instrumentalists read their staff:
Music history is full of people creating their own interpretations of customs. At some point it becomes a house style. Later it becomes a stylistic norm for a particular era/genre/etc.
I wouldn’t read too much into it and stick to what makes most sense to me. If it would harm my thesis‘ grade, I would conform to the different perspective, but I think it’s unnecessary by your professors to insist on it as if it was a universal truth rather than a stylistic choice.