It’s not a literal inquiry, it’s the verbal equivalent of a TCP handshake.

It’s protocol negotiation, volume adjustment, and preparation for transmission.

That's how I see it, and there'd be no point if no further information is exchanged. As a sibling comment says, some people use it more like a ping, where I'm uncomfortable using something other than a more traditional greeting:

That is to say, when passing someone in a hall, I want to stick to "hi" or "good morning", and feel uncomfortable if the other person says "how are you?". If it's the start of a conversation, "How are you?" works absolutely fine.

I think the problem is that "How are you?" doesn't finish an exchange nicely. You can easily greet someone in passing with A: "Hi" B: "Hi" <EOL>

It doesn't work (for me, at least) to go A: "How are you?" B: "(Fine.) How are you?" A: (optional)"Fine"

If A responds fine, it feels almost rude to abrubtly finish a conversation that had previously involved both parties asking questions about each other (even though they're really just being used as greetings). If A doesn't respond at all, that's rude for not responding to a question!

It depends, as a conversation starter it is probably okay. As an entire conversation it is almost entirely pointless, basically 2 people acknowledging that the other still exists.

ICMP then

That's not a bad thing! Acknowledging each other on the social graph.

I can't fathom why you've been down-voted on this comment! I feel the exact same way and I think you've elaborated on the parent's comment in a usefully specific way.

And I, too, find the exchange irritating and have now taken to a stock response of "hi" as a form of "nonviolent resistance"[01] to the question!

[01] https://en.wikipedia.org/wiki/Nonviolent_resistance