As soon as you said "oat milk" is "much cheaper," I knew this had to be in Europe. It's far more expensive in the US than it is here, particularly compared to American soy and almond milk prices. I believe this will change over time due to the large increase in interest (Oatly from Sweden has a North American product and now Silk is starting their own) and the existence of a significant domestic oat industry.

Is almond and soy milk a bigger thing in the US?

Yes, they're far more common. I don't recall seeing oat milk on store shelves until very recently.

According to a source, "almond (64 percent market share), soy (13 percent market share) and coconut (12 percent market share)"

http://www.mintel.com/press-centre/food-and-drink/us-non-dai...

EDIT: I should add, for those interested, that this dominance is perhaps less strange when noting that California alone produces around 80% of the world's almonds.

here in canada (bc) the oat milk is usually a bit cheaper than soy milk.

For what it’s worth, Oatly is using Canadian oats in North America.

Interesting; have you tried different soy milks? Some use seaweed extract which might give such an aftertaste (though I've never noticed).

Milk is subsidised in many markets, either directly or indirectly; but the demand side makes a big difference too. Also, things are often priced to what people will pay...

Yes, I tried a few.

It was like a negative aha-moment, a taste that was always there but I never noticed it, when it finally clicked, and I found out it was a fishy taste soy milk pretty much died for me.

Have you ever tried freshly made soy milk (i.e. made the same day from just soy beans and water in the traditional way) ?

You are describing a placebo. You tricked yourself into thinking it's fish (if anything it's algae/carageenan) and that you don't like fish (algae). You can train yourself back and enjoy the benefits of soy milk.

The texture of oat milk is offputting for me. So thick

Really? To me, it was the main selling point.

I also like rice-soy milk, it doesn't have the strange after tastes of soy milk, but it's just so thin, hehe.

I'll mix oat milk with coffee but I cant drink it plain. The texture and taste are not good.

Coffee is the main place I've experienced it, really dislike the texture vs other milk alternatives. Almond milk I think is actively better than milk in some scenarios (matcha lattes)

I also can't do oat milk plain, but with cornflakes it works out quite well.