Who asked for this???
We want a foldable phone!
No one really wants foldable phones. It's a stupid hype from people who want to force new technologies into the wrong business because they don't care about usability. Maybe it's the same group of people, who likes the ergonomical nightmare of touch displays on desktop/laptop computers.
Let me provide you one of many, many valid points. A bendable/foldable display can't use a static protective layer as glass. You have to use some kind of plastics that needs to be very flexible. But flexible plastics are not very durable and not scratch resistant. They can't be. If they were, they are not flexible enough anymore. You can't have strong and weak molecule bounds at the same time. That's why scratch resistant displays are very easy to shatter. Even if companies like Corning will let us believe the opposite - in real world conditions, they break easily. You can work the molecule structure to handle some well defined force vectors, but you will weaken the structure to other forces. You have to decide between these two characteristics of a potential cover material. If you will be resistant to scratches from dust, sand and keys, you can't get very far below aluminium silicate glass. We don't know a synthetic material, that provides bendable flexibility and the scratch resistance you will need to make a foldable phone a success. There is no magic in science.
For the most users, a foldable phone's display will scratch in weeks, if not in days.
Things will get worse, if you do it the Huawei way and put the flexible display at the wrong side.
Another point is, how the hinge section of the display will look after a year of use, if you had bent the display many thousand times. These phones will look like garbage within months.
To make things clear: I have an iPhone 4s here. It has grown a little bit yellowish over the years, but despite of that, is absolutely undamaged and fully working. No bendable phone will ever achieve that durability.
Of course, you can cover the unflexible part with glass and just leave the hinge unprotected. Nevertheless, you will have a well defined point of failure. Let Samsung have managed it to survive the first 12 months, what will be a great step forward from the two days of their first interpretation. But what's then? Will customers buy the next iteration of a foldable phone, if the last one hardly survived?
To be realistic: yes they will, but it's stupid anyway...
Even the additional screen estate doesn't provide any benefit.
For videos it's stupid. Usual screen ratios (16:9 or 21:9) will use the same screen estate as if you turn a normal phone by 90 degrees.
Different Apps side by side on a phone? Really? A phone is not a great device to work with different apps simultaneously and hopefully it will never be. It's more usefull to have a tablet or a laptop (bigger screen, keyboard, pencil, stand) than try to use serious tasks with one hand while holding your device in the other hand. At least if you do more than just instagram and tinder.
I loved microsoft's approach with Contiuum, where you can put your phone on a docking station (with keyboard, mouse and monitor) and instantly have a full featured workstation. Samsung copied that for Android, but it's still Android. A system that had been proven not to work great for tablets, how bad can it be on a desktop? A blown up phone without the phone is a stupid concept for a tablet, that's why Android phones are growing bigger and bigger and why Apple users still claim the demand of phones in a range between 4-5". We don't need a phone that is the worst of both worlds. We can have a phone that is a phone, and we can have a tablet with usefull additional features, optimized apps and from this year, we have iPadOS. A system that is the next level to separate phones from tablets.
Why do people really want bendable phones?
Because phones are near to perfection and nothing dramatically changed over the last few years.
We have full displays with resolutions that are better than our eyes, incredible computing- and graphics power as 2 years old laptops, wireless charging, wireless gigabit networking, wireless anything else. Despite of better battery life (what's hard to achieve without a chemical breakthrough) here is nothing to improve anymore. And if you like the statement or not, not even 5G will provide significant benefits to phone users. It's made mainly for IoT and autonomous traffic. A lower latency and smaller cells is nothing you will recognise and the higher bandwidth will be split to much more devices than now.
Phone's hardware is on an end. Foldable displays will not change it. We have to improve software and features. Maybe, future phones will become again smaller, because we outsource the display to glasses or retina projectors, that are freaking small to build.
To achieve the future, we doesn't need bigger or bendable screens, we need the display to come more closer to our eyes. Making a device so big, so you can only hold it in 3 hands is stupid.
There are bazillion applications for bendable displays, but not even one of them is a phone or a tablet computer. I hope, Apple thinks the same way.