I believe that if WKTZ did have to make the switch to an online-only format it might go more smoothly than other station's transitions from broadcast to internet. I made a quick stop by WKTZ (actually Jones College Radio's) Facebook page a few days ago and found many posts from their listeners stating they listen to WKTZ via their mobile devices. I would imagine the common belief is that WKTZ appeals to people who are in their 60's and 70's who are averse to technology, the internet, etc, but I did see a comment too from one of their older listeners who had heard WKTZ could be heard all over the world, and they wanted to know how they could listen, too. I am still under the great belief, however, that many of the EZ/BM listeners of today are not elderly folks, but people who are in their 30's and 40's (maybe even 20's) who either grew up with their parents listening to the music...or have found it by other means. I know this to be true because I regularly hear from my listeners who tell me they are in these age brackets I just mentioned. I know several people who do similar online EZ/BM stations and, they are in their 30's and 40's (I am 45). Many of the younger listeners have a broader sense of how to listen to online radio via mobile devices, so, if WKTZ did opt to go internet-only, I believe that many of their listeners would be willing and knowledgeable enough to make the transition.
You are right, though, it is not a question of "if" but "when" internet radio becomes fully mobile. I do tell my listeners, though, if they are unable to listen with their mobile devices while driving, it's always good to download an app such as TuneIn where they can record the station via TuneIn and then play it back in the car. It's not live, but if you don't have access to online radio in the car (or can't afford the bandwidth), it is the way to go.