Big salmon (I say that in a somewhat tongue-in-cheek way) seems to have a chokehold on all food suppliers. I swear salmon makes up 90% of the fish I see sold almost anywhere apart from a specialised fishmonger. I find it really wierd
I'm from the UK and despite being an island we have no fish culture. We used to have more, but the supermarkets that have a total chokehold on our food lives have severely limited the variety (and freshness) of fish available, making us squeamish about foods that were an integral part of our culture (eels, cockles, smoked fishes of many kinds). This is a horrible horrible loss to the diversity of our diets and to the populations of the few fish people still eat (cod and salmon).
The lack of fish culture that makes you state such an opinion is most likely caused by unsustainable, monopolistic supply chains that have shaped culture, it is not an objective fact.
Luckily, I have carribean heritage and a degree in Japanese and so I have exposure to good fish from other cultures. You know, people make fun of the fact that the British used to eat eels, but in Japan, eel is seen as the most premium, most delicious food you could possibly eat? It's more expensive than steak to eat at a restaurant, it's so sought after. Salmon doesn't hold a candle to eel.
I cannot imagine this being a common view unless you just haven't tried many fish varieties