Could Verizon be getting rid of all unlimited data plans regardless of how you get your phone? Could Verizon actually do this to all the customers that have been buying their phones at full price to keep their unlimited data? Well according to a consumer rights attorney, technically yes they can and the reason seems legit, dirty, but legit. Basically once you start paying your bill on a month to month basis and are no longer under contract they can refuse to give you service, thus forcing you into a new contract or different carrier.
Will they do this? My bet is no, especially since Sprint and T-Mobile still offer "unlimited" data, albeit their network isn't near as robust and good as verizons, but nonetheless they still offer it. Sprint is working hard to get their network to where Verizons and AT&T's are, with the soon to be finalized acquisition of Clearwire, the buying out of us cellular specturm in the midwest, and the company being bought out by Japan Softbank. They are definitely moving in a direction that will make their network very, very good and will have something to pull customers away from other carriers if the other carriers don't offer "truly unlimited" data.
Only time will tell.
Sources: Engadget, CNET, and Phandroid