Also rice doesn't grow anywhere near Germany. Today that's not really s factor anymore, because it's so easy to shop, but my parents both grew up sticking very much to a local and seasonal approach to cooking, because everything else was new to them. They eat what they always knew best, so 5-6 days of the week the starchy side were potatoes. Rice is way more filling by transportation effort, but potatoes have been around their entire lives and in my dad's case also what his parents grew on their farm.
On a related note: German beans are different. You'll find canned kidney beans everywhere because combining them with sweet corn, bell peppers and onions with a seasoning overpowered by vinegar is a popular cheap side salad (often called "Mexico salad") and you'll find Heinz beans in tomato sauce but otherwise it's white beans or green beans.
I was happy to discover canned pinto beans at my local supermarket but they were only available in a hot tomato sauce (branded as "chilli beans") - I only just found out the overpriced exotic Italian Wachtelbohnen collecting dust in the shelf next to them are pinto beans too.
Heck, I'm nearly 40 and I've met Germans my age who were intrigued (or put off) by couscous because it's so exotic and they've never tried it before. I've talked to people running kebab joints (Dönerbuden) who said that they stopped offering lamb meat because the Germans didn't buy it and the few Turkish and Arab people who frequented them weren't enough to justify the overhead.
Just on a practical note, if you're looking to buy dry beans in Germany, every Turkish supermarket has a whole aisle dedicated to them. You can get a couple dozen kinds of dry beans there, including pinto. Most organic grocery stores have them too, but for 3x the price.
What German did you meet, that didnt know couscous? Granted, im a fair bit younger, but all of my friends and family know couscous and eat it fairly regularly (im german too). Which is to say: couscous is very well known in germany in general
> couscous is very well known in germany in general
I take it you live in a city. When I lived in Cologne, everyone obviously knew couscous. Rural Germany is a very different place. Granted, this was like 10 years ago but there's a reason we have the saying Was der Bauer nicht kennt, frisst er nicht ("what the peasant doesn't know, he doesn't eat").