Here out west I'm not seeing where CB does better than a 2M or 440 rig. We have a plethora of mountain top repeaters where you will get wide coverage. Some even 100 miles from the repeater.
I can see in parts of the "flatter" regions where tower mounted repeaters that don't get that sort of range where CB might have a slight edge with ground/over the horizon advantage along with plethora of truckers monitoring (although they are declining in numbers).
If off road comms/emergency mobile comms is the objective, then why not both, or "all of the above"? Go big or go home.
There are mobile HF/VHF/UHF radios. With a simple mod they become CB capable. And before we get in to it, emergency comms as in life or limb, means all frequencies can be used!
Although I'm more in to the hobby now, I started in to ham solely for the same reason. Even today, I don't see a CB as reliable over a 2M/440. After 17 years a tech I finally upgraded to a General. Prior to all that it was CB in my Jeeps/FJ40. And unequivocally ham outperformed CB.
I will stand my ground and proclaim a ham ticket is the best bang for your buck. Specifically, get a General class and a radio capable of "all of the above" and you will no longer wonder or worry about emergency comms.
Or go simple and get your tech license and get a 2M AND a CB rig.