Some people in the know at Nokia have said adding phone capabilities is technically possible, but that doing so would bring it into an entire other market (phone market) with extra rules & regulations, add cost, etc.

They seem to want to keep the device as an internet tablet. Most people have one or more mobile phones. Should one want to connect the IT via the cellular network, they can do so via a compatible phone with data plan. There are plenty of examples of people who do so.

That said, would I like there to be a SIM card slot in which I can put an unlimited data only SIM from a certain provider at $20-30/month. Sure! Because my cellphone needs are very limited. I use my cellphone on average a handful of times per month. A post paid plan with data extension would be ridiculously expensive and underused for me.

So, I don't disagree with you. Nokia executives just see it different.