CB is dying out even in big-trucks. I haven’t even turned mine on in forever.
Traveling together with friends in separate vehicles is one of the last good uses of CB.
Other than that, they’re still the standard for communicating between dump trucks and loader operators and scale houses at gravel pits and such, beyond that there’s not much use.
A large percentage of the current crop of big rig drivers are immigrants who don’t talk on the radio and don’t even follow any traditional common courtesies like flashing lights to signal when you’re clear to come back into a lane after a pass.