There are a number of quite good modern primes that are tiny with big apertures, especially for smaller sensor sizes. Even then, though, lens plus camera is alm

There are a number of quite good modern primes that are tiny with big apertures, especially for smaller sensor sizes. Even then, though, lens plus camera is almost always much bigger than the current crop of depth cameras (K4A, Realsense D400, L500, Lucid Helios). Even those cameras is still too big for some applications, that's where PMD's tiny little cameras have a niche. There's always going to be some room for larger, better sensors, but a lot of applications are in need of more sensors to get better coverage, and size is definitely one of the tightest limitation on where they can be applied. I think this can be explained quite simply. In a fully controlled environment, using structured light but cheap lenses and small sensors is much more cost-effective. Why would they use expensive APS-C+ sized sensors, that they don't seem to be all that good at making, when you can get away with very cheap parts? I mean sure, greed is a plenty good explanation of Canon's behavior. The RV-series are pretty big and plenty expensive, so I don't think using better optics would be an issue. Indeed, if single-frame PDAF depth worked out, it would considerably speed up the parts recognition cycle time, which is actually somewhat slow due to the multiple patterns required by the structured light system. The projector and structured light processing work isn't free, either, so it seems like depth they got for free would be better in every way. Dual Pixel AF II, at least in marketing speak for OSPDAF, has been around for longer than the RV-series, so I can't help but have doubts about the actual practical applicability of PDAF SfF. But this is precisely the point of OSPDAF or split-pixel phase detection. You get both depth and RGB at the same time, because the RGB sensor doubles as a phase detection sensor. Yes, that's true, but the problem of making a good RGBD camera is that you generally want a deeper depth of field in RGB so as much of the image is in focus as possible, while maximizing PDAF SfF depth quality requires as shallow a depth of field as possible. It's not impossible to solve this, but the fundamental optical features you want out of the depth part are the opposite of the features you need from the RGB part. You could address this by changing aperture between each depth/RGB capture, although you'd definitely have to use an electromagnetic aperture to avoid lifetime issues. You'd still end up with a slower framerate taking successive depth/RGB frames, but that's doable for many applications.