Maybe I'm jaded from using smartphones for so long, but exactly what's so
difficult about using a phone?  My Nokia 3650- my first smartphone, bought
four or five years ago, had two big "softkey" buttons on the front- one
preprogrammed to launch it's browser and one to start the camera.  Hardly
"difficult to access."  Right after you snapped a picture or shot a video,
MMS-ing it or e-mailing it was two button presses away- Menu, Send.  It
didn't have a touchscreen or the slick iPhone UI, but unless your IQ was
less than that of a cactus, you could take pictures, use e-mail or browse
the web without any real effort (except entering a long URL by 12-key- that
phone really taught me to use favorites!)  

Personally, I prefer a touchscreen based UI like the iPhone's or my Windows
Mobile-based phone to a 12-key like my 3650 used (except, of course, when
trying to make a phonecall!) but despite Steve Jobs' keynote rantings of a
year ago, cellphones were not some sort of arcane indecipherable objects!

Frankly, I think a large part of the iPhone's "lead" in mobile internet use
(i.e. "most used mobile browser", etc.) is due partly to the fact that
Apple and AT&T held a gun to their users' heads with respect to buying a
data plan.  "All you can eat data" was "included" with all iPhone plans, so
many people now had the ability to try mobile internet that perhaps never
plunked down the $20/month in the past because they didn't perceive the
value.  (A similar product in that respect, IMO, is TiVo, or any DVR- those
who've never tried it wonder what all the fuss is about, but once someone
uses one, they're typically hooked.)

My wife, for example (my oft-used luddite example!) never fooled with a
data plan despite my urging, until she was issued a Blackberry at work and
became hooked on mobile e-mail.  Now she has a data plan and smartphone for
her personal use as well.  She never would've "discovered" the value of
mobile internet unless it was forced on her (in this case, by work.)  If
her personal plan had "included" data, she'd have embraced it much sooner.

Similarly, I suspect quite a few iPhone owners may have had phones with e-
mail and browsing capability that went unused not because of "difficulty"
but because the users never before opted to pay for data, again due to
carrier's lack of marketing- part of the iPhone marketing genius was also
the single "forced" data option- at the time of launch, Cingular had a
plethora of confusing data options with varying MB "buckets", different
rates depending on phone classification (feature phone, smartphone, PDA,
etc.)  For most (non-iPhone) customers, buying data was probably more
confusing than using it!

If carriers tossed in a free month or two of their extra features (data, GPS,
mobile TV, whatever) like satellite and cable companies often toss in a
free month of HBO, I suspect they'd be surprised by the adoption rate once
people saw how convenient these features are to use.  But as long as the
advertising pitch remains how long you gab, and to whom, for $39.99, data
will remain a niche product, and the Apple marketing message- you can only
check the weather or the NBA all-time high-score leader on the iPhone- will
ring true on many eyes and ears.