I don't think that's a satisfactory answer. It would absolutely be possible to sync the layout between even such different devices as an iPhone and an iPad. The fact that the iPad moves things around between landscape and portrait is irrelevant. Make them the same in portrait on both devices and let them move where they want to in landscape. At least they'd be in the same folders and on the same screen.
Agreed, the iPad uses a different number of rows and columns from the iPhone, even between its own Home screen and other screens, so it is certainly not beyond the realms of possibility to give the user the ability to set the number of rows and columns on the iPad so it can accurately mimic the iPhone - at the discretion of the user. Don't need that? Don't bother setting it, but for those who need to avoid the chore of trying to keep the layout of hundreds of apps the same on multiple devices, they would be able to. And make no mistake it IS a CONTINUOUS chore. Every little change on one device requires faffing around with the others, trying to remember what was changed.
iPadOS and iPhoneOS are not that different to make this a problem. Just another red herring. Not like it's Windows and MacOS.
Besides which, I have a need for such syncing between 2 iPads and they are EXACTLY the same in terms of OS and also row and column count, so any arguments that rely on those parameters are simply not valid. Apple even provides this exact function on the AppleTV so are aware of its value.
So, in summary, there is NO reason whatsoever Apple cannot provide either the exact layout sync function that so many users desperately need and a slightly modified one to deal with differences between iPhone and iPad screen sizes. They have simply decided not to bother. Just don't pretend there are technical reasons for not doing it.
