This is because according to the tweet, Apple is still slightly skeptical and cautious about adopting the foldable design. This is because they aren’t sure if the trend of foldable smartphones is here to stay, or if it will eventually stop being cool, kind of like how phones with glasses-free 3D displays eventually stopped being popular.
https://twitter.com/dylandkt/status/1479157616983130113
The tweet also says that Apple wants to make sure that if they do adopt a new form factor, like a foldable, that it won’t be a “regression” of the current form factor, meaning that it should be better, not worse. So much so that they are playing the long game to see how foldable technology progresses before they decide to hop on board.
Apple has been known to take their time when it comes to adopting certain features, so this move shouldn’t be surprising. Plus, if you recall, some have suggested that in the next 10 years or so, Apple wants to replace the iPhone with smart glasses, so we’re not sure how developing and releasing a foldable iPhone is supposed to help with that goal.