I'm not sure that is such a strong signal. The minimum return policy by law in EU is 14 days. IKEA has a one year open box return policy. I would not argue that modern IKEA is high quality.
I'm also sure I have seen other stores with a 1 year return policy, though I can't remember which ones off the top of my head.
(That is "return undamaged working product" return policy, not warranty policy. Exceptions apply to perishables, underwear, etc. At least here in EU they are different. Warranty is, depending on product category, typically 3 months, one year or two year minimum by law.)
Ikea is not high quality compared to most gallery-style furniture. If you're buying flat-pack furniture to assemble at home few brands will serve you better.
Oddly enough, none of my bookcases in my new house are Billy ones though. Yes, I still have loads of physical books. I found a Chinese brand of all-metal bookcases that are lighter weight than Hon or Steelcase but hold a lot more weight than Ikea bookcases of similar price. They don't suffer from the famous bowed shelf problem most MDF shelves get. They're also packed flat. They even disassemble and reassemble neatly for moving or storage. It's Oseillc, which is a brand of Outstar Office Solutions, Ltd. They also make a little institutional, industrial, shop, and retail furniture under the parent company's own brand.
For books an important features is that the shelves have doors and a back, to have to dust off the books less often. Do yours come with that? I'm not finding that brand on any Swedish retailer from a quick search either, so not sure how relevant it is.
I have some older Billy shelves that have been very solid, even when overloaded with books (I too have a lot of physical books, a lot of them older and not available as anything except physical, quite a few even predating the ISBN system).
Mine from that company so far are library-style open shelves. I have a vacuum attachment I like for cleaning shelves and books, so it doesn't require a feather duster. I keep certain books inside doors and backs.
The same company also makes cabinets and enclosed cases. They are available via a handful of retailers in the US. The big one is Amazon. I would have guessed they sell and ship worldwide since they're on Amazon. It appears I would have been wrong. I can't find the brand on the sites for Sweden, UK, or Germany. If I set my delivery to Sweden, I can't even find them on the US site by searching but can still see their store page. They don't seem to be on AliExpress either.
I would argue that Ikea sells a spectrum of quality. Much of their cheap stuff is priced according to quality. Much of their expensive stuff is too.
I have some of their more expensive solid wood furniture and it is really quite nice. I have some of their particle board college student grade stuff and it is pretty lightly built, but an incredible value when compared to other vendors at the same price point.
I'm also sure I have seen other stores with a 1 year return policy, though I can't remember which ones off the top of my head.
(That is "return undamaged working product" return policy, not warranty policy. Exceptions apply to perishables, underwear, etc. At least here in EU they are different. Warranty is, depending on product category, typically 3 months, one year or two year minimum by law.)