Really? I doubt that logic is sound.
How about this logic instead? In 2006, unlimited data on crap phones on Edge or first gen 1X CDMA could possibly eek out a couple hundred MB/mo. In 2007, the iPhone and late gen WinMo phones on Edge/3G/EVDO might be able to eek out a GB, or if tethered, much more (so the carriers killed tethering.)
In 2008-11, iOS/Android devices with HVGA or better displays capable of video, decent 3G modems capable of pulling full speeds, and other improvements, coupled with ready access to high bandwidth content, meant "unlimited data" could run into tens of GB of data. (The carriers killed unlimited data - except as a stunt to gain subs for VZ or as a last gasp to retain subs by Sprint or TMo)
I do expect the carriers (all of them) will make sure the average profit per sub remains constant (or increases) over time, since the carriers are all for-profit corporations and not nationalized government service providers.
This is capitalism. We love it, remember?--
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