bhunter
The Spherical Cow
The OP asked about the market segment the speaker was aimed at and market segments are by their nature a divisive thing. You know as well as I that a big part of marketing is indentifying groups of people and then appealing to the aspirations, fantasies and self image of those groups. That's simply the way of things.
I concur. After looking over ARs marketing from the 70s, they were targeting the discerning audiophile. They sought to couple jazz and classical, both of which arguably are more sophisticated than, say mere rock, with their speaker line. Infinity did the same thing albeit later in the 70s with their pictures of orchestra instruments in their ads. Whether or not one likes Miles Davis is not the issue. AR certainly thought that he would add a certain sophistication and gravitas to their campaign for their products.
The OP asked a direct question regarding market segment. Let's see AR speakers, jazz, Mercedes cars, and a good single malt. I always thought both the AR and Infinity ads were very dignified and exuded a sense of style and sophistication. Both of which some would consider pretentious. The whole point of advertising is to place your product away from the competitors, that is, to divide.