I DEFINITELY notice.
I understand what they were going for, but the experience I'm getting is not what you guys are getting, at all. I hear the music clips when I go into a sanctuary, and as soon as I leave one...and that's it. Pure silence and boring ambiance the entire rest of my time in the field, with few exceptions where another track actually kicks in when I move to another area.
It's like Monster Hunter, you hear music for like 20 seconds and the rest is dead air until you fight something. And it sucks, IMO. I just wish they'd put the themes of the area on cycle, where you hear one, then say, 20 seconds of dead air at the most, then another theme from that area plays, repeat.