When you get news like this, I'd analyze it from following angles:
1. Why it is designed, for whom and what use
2. Experience and capacity
3. Likely price, sellability and profitability
1. Starting from the design, all touch devices are now can be divided into iPad-type, pure Android, touch only and mixed use, such as iPads with keyboards and Microsoft Surface devices, some variations of Android like Dex, a bit of hybrid devices. So who is going to use these large foldable devices? Obviously people who large screens on go. There can be few fields such as musicians, video and photo editors, artists who'd need such large screen on go (remember it is close to 19 inches, so it dwarfs even large 16 inch macbooks), yet without the bulk of built in keyboard or trackpad. So, yes, the device can probably connect to physical keyboard and trackpad, but this will negate its true purpose of large screen on go in lightweight way, so its primarily inputs are touch, and virtual keyboard and trackpad on the screen.
2. Apple has enogh expertise to build such a device. Microsoft is also a big player in this field with its Surface line and it began experimenting with hybrid OS since Windows 8 times and it did create a Surface table prototype. I'd say Microsoft and Apple are both world leading players in this regard.
3. The device (19 inch) will probably weight about 2 kg, or close to two iPad Airs. It will also may cost about 1500 dollars, again close to two iPad Airs, maybe more initially. The device will house Apple's CPU, GPU and modem and therefore, create another market for Apple devices and components. How much it will sell? Larger screen is a major factor so I'd say some artists may buy it as well as rich people.
4. What OS? I think that it has to have MacOS to be sellable. A large ipad even foldable, is still limited by iPadOS. Macs with built in touch capacity is a fascinating idea.