If things were set up to only mount the filesystems while they're being modified to update the kernel, I can see the value in that. I'm guessing that's not being proposed here, though, because it's too much friction to change the current boot system scripts, and automount doesn't incur the same friction?
Even then, what would it change? The only time those filesystems are being written to is for a new kernel, a new bootloader, or a bootloader config change. In every one of those cases, the filesystem still has to be mounted, so I'm not seeing what the benefit is of keeping things unmounted right up until you're going to write something. (Basically, I can't seem to see any version of this that reduces the actual total writes to the filesystem.)
