As for how ‘rare’ a bird we might be, it really depends.
Economic level, generation and personal interest all drive whether one finds a greater density of people interested in audio for Audio’s sake.
I live in a high-end community, where the average age is like around 63, so I’m “the kid”.
Therefore, many of these people come from a generation where listening to music was an act, not a passive side-effect.
Quite a few have decent audio systems; some even have all out Meridian Digital theater setups (six figure stuff).
They even admit to listening to music vs just using it for TV/Movies.
But they are indeed a minority (less than a percent best I can tell), even in this place.
And even the most die-hard audio guys (they’re all guys) think I’m absolutely nuts. But to a person, say that my system is the best they’ve heard
So while people might not want to invest on their own, they sure enjoy hearing a high-end system.
But I have a new criteria for what a ‘serious’ audiophile is: One that dedicates a room to the pursuit of audio, including extensive acoustic treatments to improve the experience.
Of the folks I referenced above, I’m the only one with a treated room (three others have dedicated theaters, but untreated (for now, I’m bending their ear on that topic). And once they heard my room, they all agree that the room is indeed a big part of why a system can sound great or not.
So, what’s the percentage of ‘serious’ audiophiles? Or maybe we should just ask, how many?