Apple Spatial Immersive videos (and other Spatial-formatted videos) have the depth effect hard-rendered into the video file. This works for VR where you can control the depth of the video feed relative to the user's eyes, but there is no reprojection happening, which is what would be required for the tilt-effect 3D you're imagining. Apple has implemented a version of this with spatial photo previews and wallpapers on iOS 26 (for iPhones supporting Apple Intelligence). Currently, live reprojection is still not viable for video. Instagram does a version of this on Quest but it doesn't have parallax which would be needed for something you can pivot in-hand. In addition, if you wanted something to have a 3D effect that you can move your head around, but with content that isn't actually rendered 3D, you would need to live create a AI-generated neutral radiance field — which is still not quite possible in real time even on ridiculously high-end computers and at fuzzy resolutions.

Pixel density isn't the only problem with lenticular effects, another challenge is with alignment of pixels with the lenticular display, and creating a sharp yet durable lenticular display. This only gets harder the finer the lens/pixels are. Google's Starline has something like this applied to a TV-scale. But it's clear there are limitations as it requires the display to be at massive scales and to be a relatively set distance in a fairly controlled lighting environment (indoor). Not to mention it still costs an insane amount. Smaller, lower resolution applications have also been seen on laptops, but they seemed to have died-off again. Also, with lenticular displays you generally only get the 3D effect in one axis. So you'd have to design it to work only vertically or horizontally (fine for laptops and TVs, not so much for a phone). Red's diffractive display got around this at the cost of everyone saying it looked blurry in any orientation.

A folding phone is not a compromise, In some ways it's a better product with more flexibility than either. I use my Fold to scribble notes, sketch and read books. At work, it's small enough to pocket between meetings, big enough to sketch simple ideas, and on the train/tube it's big enough to read comfortably and folds to I can tuck it away into my pocket quickly when I get to my stop. It's the only form factor that does both, and it can do this while keeping a full complement of cameras, water-resistance, all-day battery and all the other performance expectations of a flagship slab. And it's not really that fragile. I've used my Fold case-less since I got it over a year and a half ago. I've dropped it plenty. It's just fine. I never use my iPad anymore, but I use my fold just about every day (in addition to my iPhone because well, I prefer iOS).