Phone manufacturers had to be creative; they were releasing the same, rectangle phone without buttons. They needed to spice things up and satisfy consumers.
The first set of consumers were tired of big phones that were not compact and compatible, and the second set of consumers wanted a big phone that could get bigger and become a tablet, once done with the tablet version, it can be folded back to a big phone.
To achieve foldable phones, the industry needed to fine-tune two technologies; the hinges and the flexible OLED display. LCD is restrictive as it has different layers, and some of the layers cannot be bent and are not flexible.
But with an OLED display as long as the little diodes inside the screen are airtight, then you can put anything you want and make sure the connections are not broken inside.
The most expensive technology on foldable phones is the foldable displays. Sadly the two things which are crucial to the popularization of the smartphone are the two things that screw up the reputation of the phone the most.
The soft screen and particle ridden hinges; these two components alone have given foldable phones bad reviews. The screen being the worst as sometimes it would have display problems and the hinges attract dust and other particles.
What would change things for the foldable phone is Apple coming into the scene and releasing a foldable Apple. Apple has registered a patent for a folding phone, once released Apple with its fans might wake up the sleepy fold phones.
But Apple and other manufacturers need to change the bulkiness of the phones, and make them thinner, reduce the piece as fold phones are more expensive than flagship phones.
And lastly, the manufacturers need to make them more durable. Only time will tell if Foldable phones are just a phase or are here to stay.