Yes - but if you're bowling along above the MILTICOM level - IFR traffic get directed frequency transfers from ATC?
And VFR just hope that they are listening on the appropriate, or just don't bother listening to anything? And that hemispherical separation and a big sky will keep them safe?
And if you want to enter controlled airspace, or upgrade to IFR with plan details - you just call the nearest transmitter and spend some time being shuffled to the correct frequency rather than being able to determine it yourself?