they're not going to survive. The history of new technologies is awash with "sure fire" companies that didn't make it. Personally, I can't ever see myself paying for radio.
There are ample statistics on the take rates of factory installed XM. We know, for example, that over 60% of people who buy a car that is factory equipped with XM will become subscribers. 40%, which you may be a member of, won't. Not now, at least.
The 60% take rate surely will not hold for Hyundai -- not because of the cars they're in, but because they are going to Standard Equipment rather than Factory Installed Options. But 50% is likely.
I've a lot of people say this until they try it. What most don't understand it that isn't "radio" in the sense that they know it.
Personally, I can't ever see MY self counting something that would make my work and drive time more relaxing out without trying it. But that's just me.