I think this has to do with the type of fish typically used in western cuisine, which is heavily biased to larger fish that can be cooked as filets or have less bones.
Asian cuisine makes much greater use of smaller fish that are oftentimes cooked whole, so the range of options tends to be larger as well.
Western cuisine is far from homogeneous. We use plenty of small fish in Southern Europe (and we eat a lot of fish) - sardines, blackbelly rosefish, atlantic horse mackerel, blackspot seabream, etc.
Asian cuisine makes much greater use of smaller fish that are oftentimes cooked whole, so the range of options tends to be larger as well.