Acura is a low volume producer. This helps keep resale higher as it is just plain hard to find used vehicles...I was looking for a used TSX as a commuter ride and the pickings are slim.
Also I think the Acura buyer is different from the MB/BMW/Lexus buyer. To me Acura is the non-luxury luxury brand. The new ones are meant to be more flashy but are just ugly. The old ones are pretty anonymous; this attracts people like my neighbor who like nice things and are wealthy (relative to most people) but don't want to flaunt it. He drives a Legend (no kidding) and she drives an older MDX.