Not quite the same situation but when my grandparents moved in with my parents, they set aside everything in their kitchen into storage and it sat there for 30 years until they died. I save a few things then set most of it out on table with a free sign and 99.99 percent of it got scooped up quick. A fed ex driver told us they were new to the area and almost everything in their kitchen came from our table.

I don't think small family heirlooms are the issue OP is trying to address. It's about naitivity of the older generation(s) passing down items that had fit their lifestyle, but their generation made it difficult for the current generation to have the same standards of living.

Nobody wants any of them, they’re old and pretty and also worth exactly zero euros.

You'd be VERY surprised.

antique furniture

you mean antique or just old. Not the same thing.

My grandmother's house. I have two sewing machines, a 6-place dining set, fine china to serve 8, two sewing machines, several rickety old pillar tables and candle stands, a cabinet full of random glassware, a drawer full of ratty, yellowed old doilies my father "remembers from when I was a kid." At least three unassworthy antique rocking chairs that are too delicate to serve a purpose...So much shit my father wants, but won't move into his own heavily cluttered house.

My wife's grandma offloaded her fancy china on us. When we brought it to Goodwill, they went "Parents or Grandparents?" And they told me this is like their tenth donation this week.

Never met her but there's a chance she might genuinely not have known.

My grandparents and great-grandparents thought a lot of family stuff was worth something but they never actually got it professionally valued. One thing that really stuck out was an ornate silver tea set that looked really nice, was in great condition, was a complete set, hallmarked, turned out to be worth fuck all because nobody actually wants silver tea sets in the 21st century, but they were a big thing a hundred years ago so there's millions of them out there flooding the market.

There was also a minor hoo-hah over inheritance of the family piano, which then turned out to be a mass-produced budget model that was no longer physically able to be tuned to concert pitch without risk of damage. Turns out budget pianos don't become antique, they just become old and you have to pay someone to take it away.

I have one, my parents have one, and I just found out that the person I'm dating has one (technically her parents have it). So they must not be too uncommon.

Huh, I've only seen dining room tables that could expand using table leafs. The only time I didn't have that was when I lived away in college because why would we have that if we just ate on the couch lol

Shape shifting tables are actually quite common! There are quite a few types:

• Tilt Top Chair-tables. Hinged closed, it's a table about the size of a poker table. Hinged open, it's an armchair, with the tabletop forming the back.
• Drop-leaf tables. I've seen these in several shapes but the typical pattern is a long, thin rectangular table with hinged panels that can be folded up to extend the top. They can be folded to as little as 18 inches wide and stowed against a wall, you can open the free side with it still against the wall to seat a few people, or you can slide it away from the wall, open both leaves and have a full size table. Stowage of side chairs is a separate issue. The shakers were fond of drop-leaf tables, and made some truly huge ones that could seat a dozen people or more when unfolded, but would stow very efficiently.
• Extending tables. My dining room table is one of MANY examples, you'll find them all over the United States because it's objectively the worst of the lot: The long apron rails aren't continuous but attached by a slide mechanism. The tabletop is split in half, so you get two table halves that can slide relative to each other. A gap can be opened wide enough to admit one or two lift-out sections to make the table longer. My dining room table can collapse to seat 4 around a (mostly) round table or extended to seat 6. All the additional hardware plus the two extra apron rails necessary make the table heavier than it should be, the slides never work right and if you prefer to have it collapsed, where do you stow the leaves? I guess with the two side chairs you nearly never use.

So fucking spot on that it's kind of unbelievable that I'd never thought about this before