Even when talking about driver updates, the argument is nonsensical. Android updates already require a full reboot of the device at the end of the update process, so new drivers can (and are) already be loaded into the kernel.

The update problem on Android is indeed a policy issue, not a technical one.

Based on what I've seen elsewhere in these threads, the idea is that a stable driver ABI means that manufacturers/chipmakers need not rewrite drivers just because there is a kernel update, removing that as a block to doing said kernel update. The willingness of Qualcomm to do the driver updates for a given chip to work with the latest kernel in Android was a big determiner of which phones have any chance of getting the latest Android, for example.