I think foldables have found a niche market at the moment. People buy them, just not in the quantities the companies might want.
The main reasons for this are Samsung being stagnant on its innovation with foldables (Z flip 5 notwithstanding), much of the competition being limited to China only or aren't being marketed at all, and the book style foldables all being overpriced (they still MSRP for $1700-$1800 plus 1000% storage markups, they should be aiming for a $1200-$1300 MSRP).
Here in the US, we have:
The usual Samsung foldables: The Z flip 5 which is a great device at on okay price, and I've seen a few of these (or the previous gens), notable because 85% of the devices I see are iPhones. The Z Fold 5 is stagnant and overpriced.
Pixel Fold: Hahahahaha it can't even last a week before the screen dies lol lol haha
Moto Razr Flip 40 and its variations: Nobody knows that these phones exist, and the ones who do struggle to even find a place to buy the phone. On Amazon listing for the US version is blended with the international listings and is often out of stock, and Motorola's website gives me an error when I try to get to the buying process on its phones. Also there's like 3 different versions of this phone Real shame, because they are good phones for a great price if you can stomach the poor battery life.
OnePlus Open: Possibly the most innovative phone of 2023, this phone 1-ups the Z Fold line in nearly every way, although it's still pricey. But again, basically nobody has even heard of this brand, much less this phone. They just believe Samsung is the only one that makes foldables while they choose to buy the latest iPhone.