I can't say it any better than that, and here is some good data on the cellular industry:
http://www.pcmag.com/article2/0,2817,2397688,00.asp
Highlight:
"
Approximately 44 percent of Americans now own smartphones, up from 18 percent two years ago, "
That's phenomenal growth, and like Greg said it takes a lot of infrastructure/cost to keep all of these data users happy...but at $20+ per month, per data device, they are raking in the cash. And with only 2 or 3 real players in the US, it's not hard to see who is holding the rakes. (Although, I also bought Sprint (S) at $5 and so far that's not panning out well at all).
AND
That leaves a large majority as untapped data plan customers...data is a cash cow, and it's only in its infancy. IMHO.