I see what you're saying, radleyp, that you can't just be paralyzed by the fear of "what if they do this or that." And I also agree that Kindle's EVDO is not presently costing Kindle users anything extra to use, beyond the price of the device itself and whatever content they buy for it. And also that Amazon is, for the most part, unlikely to start charging for it, both for the very good reason you cite, and the ones I mentioned above.
The reason we're pointing it out is that this is the sort of thing folks like to know might happen in advance so that they can make an informed decision as to what they think of the concern's likelihood and impact, rather than being surprised by it later. That's all.
You can never know everything, of course, but finding out as much as you
can know, and evaluating the various bits of information as to how big a concern they are to you individually, compared to your individual needs and wants is a good way to increase the odds that you won't regret a purchase.
Of course how much research each person will need to do before a purchase to be comfortable with it is going to vary from person to person. As it should -- all of our circumstances are unique at some level, even when they're quite similar.
Just because one person has concerns about whether the EVDO situation and/or it's possible
eventual ramifications is right for them doesn't mean it can't suit the needs of a second person to a "T."
If you're happy with your purchase, wonderful: that's the important bit, finding a solution that suits each person's needs as best as possible (I know: I say that a lot

). We're just trying to share as much info as we can so that folks can make informed decisions, so they're more likely to be happy with them. Some folks care about future possibilities, and others wouldn't give a rat's spleen on the point. That's okay, people can usually figure out for themselves whether they're concerned about a given point.