Skype is petitioning the FCC to demand that U.S. mobile operators loosen their controls on their networks to allow access to any service or site. I don't think anyone argues that the operators will move in this direction on their own at a controlled pace once they have the infrastructure in place to support their own business goals.
As they look to grow their subscriber base with kids six and seven years of age, they need to be able to ensure that children don't have access to inappropriate sites. Moreover, given the millions of dollars they've paid for spectrum and to build infrastructure, why should they be forced to open their networks at this point, at least, to competitive services that will cannibalize their own business? especially when they can't control the end user experience and will be fielding the customer service calls when consumers are dissatisfied?
I believe that they will continue to move in the direction of more open access (and, yes, there are times when I wish it would move more quickly so I could use all of the bandwidth-intensive applications and services I'd like to use at my fixed rate all-you-can-eat data plan), but they have a right to use their investments to return value to their shareholders. Market forces rather than the government will move them in this direction.
And, I have used Skype on Verizon's network – they let me do so on a more expensive data plan. The experience was mixed – sometimes quite good and at other times, really, really poor such that I just told my friend I'd call her later from a phone.