[pathartl]

I think when they moved to the M series they had trouble providing enough PCIe lanes. Not that I ever really trust Apple to ever offer non-proprietary storage again, but moving the storage controller to the SoC probably avoids any PCIe support they'd have to think about.

[simondotau]

Moving the storage controller to the SoC makes sense for Apple because they already did the work for iPhone/iPad, and it reduces part count. Having no upgradeable parts inside probably also reduces failure rates. It's not the trade people here would make, of course.

[my123]

Communication from the in-SoC NAND controllers to the NAND chips themselves is done through PCIe AFAIK