The author has thrown together thirty things that are, to borrow a phrase, not like the other.
For example, serial marketing & this-year's-fad products were only 'collectible' in the pitch that sold them. They're not. Big deal.
Much of what she has to say is about unrealistic hopes, eg, that the train set gathering dust in your (not her) basement is 1) collectible, and 2) valuable. Okay, it is neither. That does not mean that collectible train sets were never collectible, or are not still collectible.
Yes, you cannot sell your children's badly worn children's books to a collector of children's books; this is news?
A local thrift shop dumped all of their worst costume jewelry into a display case prominently labeled "The World's Worst Costume Jewelry" ... and the stuff flew out the door at five bucks per. The manager, who wrote the sign, could only shake his head. "Forty-five years in this business, and I'm still learning."
The "brown furniture" thing is interesting; eating out has been wreaking havoc on the prices of all the bits'n'pieces of entertaining at home, including the dishes, the silverware, the serving pieces, the furniture that you set them on, and the furniture that you store/display them in.
Other lifestyle changes count, too:
Why Are Antiques So Cheap? Because Everyone Lives in the Kitchenhttps://www.nytimes.com/2018/10/26/...-living.html