Citizens Band is still the predominant platform for radio communications among offroaders. While some have turned to ham radios, UHF "race radios, and FRS/GMRS radios in search of more effective technology they are a minority and are likely to remain so for the foreseeable future.
The California Four Wheel Drive Association (Cal4Wheel) and Jeep Jamboree require CB radios as mandatory equipment for participation in their events, as do many jeep clubs nationwide.
I have CB and 2m ham in my jeep. The ham radio gets relatively little use because very few jeepers in my area have them, including the members of my jeep club and the other jeep clubs in the area. However, I am also part of an informal overlanding group that gets together 2-3 times every year and requires all trip participants to be licensed hams with 2m radios. It is one of very few that does.
To me a ham radio is a nice to have addition to your off roading kit. Especially if you like to wheel alone. (Not recommended).
The test has been simplified over the past few years.
I know of a few groups that use them and require that you atleast have one. While a license is REQUIRED to transmit anything over the channel. It does not require a license to listen. But what fun it it to listen to people and not talk. (Kinda like lurkers on a forum)
Plenty of off road groups around have free classes for the license. They want people to be legal and know how to use them properly.