There's definitely selection bias in play, but I think for household objects (such as you may find in a junk/antique store) material science plays a role.

Two things come into vogue in the mid 20th century; plastic and electricity.

Plastic does not age well. It decomposes with exposure to light, so pretty much all old plastic looks pretty bad. Personally I never buy old plastic even if it looks good, because, well, plastic.

Secondly electricity. Electricity things again do not have good longevity. (In the shop were a few old-style hand cranked cast-iron meat grinders. They'll still work perfectly 200 years from now. The plastic attachment to my Kenwood mixer; not do much.)

For furniture, material again comes into play. Solid (hard) wood new furniture is very expensive. (As it should be.) So most wooden furniture made now is either soft-wood, or manufactured wood, or both.

I buy old furniture from time to time, but I also do what I think lots of people did in the past (and which has not survived) recycle wood i have to hand for practical purposes. I don't expect these to live beyond the room I'm making them for.

There are maybe a few hundred thousand violins from Germany circulating in the United States that are between 100 and 300 years old. In my high school, nearly every violinist was using an instrument that was affordable and older than 100 years. These are still delicate. It's a weird piece of insight porn to always point to selection bias, I mean it's very well possible that as long as it weren't destroyed by some big trauma like a fire, maybe every old violin has pretty much survived.

Is it a selection bias, a survival bias, that says that violins are particularly durable and fancy if they didn't accidentally light on fire? No. I think the author is completely right that it has to do with functionality and taste.

Because we already disposed of the more-plain, less-durable stuff that didn't survive the cut between "Keep," and "Trash heap"?

(Yes, it is perhaps the case that this all conspires to form a bit of circular logic. It happens sometimes.)

I guess because businesscosts weren't calculated to be as competitive as possible and labour was far cheaper, so it wasn't a problem for people to take their time and build solid things. Now we just want super fast machines that produce as much as possible with the least amount of humans involved.