About the cost of data plans: Very true. This is what kept me from the Samsung Omnia which I was in-store and ready to plunk down the cash for even though it wasn't my ideal device.. then I learned a data plan was mandatory. Got myself an Alias and went on my way.
But to that end, it might be in the financial interest of a carrier to introduce a "basic smartphone data" plan, say $15 a month instead of $30, with a data cap and so forth, alongside a $100 handset. It's something I could see happening as smartphones start to occupy a greater portion of the total cell market, but we're talking decades off, I would think.
@above, but most users won't be choosing one or the other. It's not that it's not a decent deal, and now (I have a steady job, whereas I was a starving college student when I got my Alias) I'd be more than willing to pay for it. But plenty of people who are currently using dumbphones won't be able to justify an extra $30 a month, $360 a year just to get a new phone.