Can you permanently disable rootless on OS X?
The following should be possible.


Download and install rEFInd to your EFI partition.
Use the Mac Startup Manager to make rEFInd the default system to
boot to.
Configure rEFInd know of OS X and to not search for any other
operating systems. (This decreases boot time.)
Configure rEFInd to operate silently and to boot OS X.
Configure rEFInd to disable all or part of SIP before booting OS X.


Normally when you start the Mac, OS X should startup (after first silently booting rEFInd). SIP will be in whatever state you configured rEFInd to set it to.

If you reset NVRAM, then you may have to hold down the option key and instruct the Startup Manager to make rEFInd the default to boot to. I say may because I am not sure if resetting the NVRAM changes the default operating system to boot to.