It sounds like you're describing survivorship bias.

https://en.wikipedia.org/wiki/Survivorship_bias

Yes, that is a more precise term that I should have used. On the other hand, I’d argue that survivorship bias is a type of selection bias.

I've got one specific example, where I know the quality has changed. I've bought the same modelf of sofa about 10 years apart. Ikea has done some serious value engineering. Both sofas look very similar from outside, but they are in fact very different. The newer frame appears to be somehwhat lighter, yet sturdier at the same time. The cushions however are now lighter and far less comfortable. They obviously spend a lot of effort into making everything more efficient and cost effective - some of it at a slight cost in perceived quality.

I should have written that the overall quality hasn’t changed. A lot of products have changed, in one way or another, but the overall quality isn’t worse than it used to be.

I think it has. It is a subjective judgement but they used to have more products that were of higher grade than they do now. As an example, my parents had a garden table bought about 10-15 years ago. They now bought another one, very similar but still not. The finish was less exact, and the entire impression a step down. With the tables next to each other, very easy to see which is better made.

But you can find examples where the shift has gone the other way too. They have always, and still have, a range of qualities. We just bought a pair of armchairs that seems to be quite solidly built and with nice material and finish, but I also had to throw away some kitchen chairs after just few years that we bought in 2010 because they were falling apart. In my experience, even pieces that has the same name can change from year to year (in either direction quality wise), because they have found a way to rationalise the manufacturing further or found a different factory that will produce it slightly cheaper but with slightly different standards.