I'm not sure that's quite right - the anti-context has shrunk since the 60s because it's harder to avoid hearing music of all genres, everywhere you go. If you have any vague interest in the music (and hence being part of the relevant context/anti-context) then you will (consciously or not) absorb it wandering round shops, watching adverts on the telly, hearing the person across the office's mobile playing the intro to The Final Countdown over and over again. Music is thrust upon you and it's not just pop - I remember being flabberghasted that a bit of continuity music for 'what's coming up next on BBC2' was off Michael Mayer's Fabric 13 mix!

So perhaps the change has occured in the greater use of pre-existing music for telly/film/ads/hold music/ringtones rather than commissioning someone to write music especially (interestingly this type of music has never been of much interest to the pop music fan other than as a novelty hit, but Great Aunt Betty will probably have a copy of Greatest Bond Themes in her dresser).