Freedompop said from the beginning they were going to use Clearwire and an additional partner to provide "free" nationwide 4G. Clearwire has always been a metro 4G network, not a nationwide network, and even in metro areas has swiss cheese holes, as teamrep is so fond of reminding us.
What's slightly new or different is that they originally claimed 4G nationwide by the end of 2012. Later it was announced they would add Sprint LTE early 2013. Now they are resorting to Sprint 3G as a backup because Sprint LTE still has very limited coverage, speed and capacity, making it not much better than Clearwire's WIMAX network.
Much of freedompop's shift off of WiMax will be increasingly absorbed onto clearwire's network via it's TD-LTE capability in sprint's most dense operating geographies. That is the one aspect of clearwire's 2-year, flat-rate WiMax arrangement with sprint that helps to smooth that glidepath.
As teamrep states, sprint is building it's network to leverage clearwire's spectrum in dense geographies regardless of where the minority-owned half of clearwire ends up. Sprint has always known that re-purposed nextel spectrum wouldn't even come close to handling the volumes that it would experience in highly dense metropolitan areas, and building cell sites so densely that they go well beyond even clearwire's propagation constraints makes little economic sense.
I know a fair number of people who limit their wireless subscriptions today because they can't even come close to streaming high-def video in locations where they want to stream it. Once they can... and they do... then they'll also be streaming it in metro locations that can't even BEGIN to handle it given the current loads. I experience latency on my subscription all the time that bears witness to the load my provider is up against.
You have likely pointed out an underlying development: I think that Sprint is deferring wholesale access on their LTE network for now because of reactive lack of coverage and capacity. That will change as they bring up new spectrum. Sprint is expected to gain an additional 5MHz of AWS spectrum access that adds to their current spectrum and plans to stop Nextel iDen network to free up spectrum. I don't know the exact phasing in of these networks/capacity, however, it makes sense for now to emphasize 3G rather than 4G. Sprint is much more circumspect in how they portray consideration of DISH's offer... I think they are fairly confident they will move ahead and will have access to 2.6GHz spectrum under existing agreements even if the 'vote is not in' that finally resolves the acquisition. If that's the case, then Sprint can plan on opening up the combination of capacity by late next year with the timing of AWS FCC auction process a remaining uncertainty.
Meanwhile, Verizon has 30MHz of AWS spectrum to layer higher capacity LTE service and make use of their content agreements with cable and OTT service providers. And other operators are bringing up higher capacity LTE and pressuring Sprint on price as well as the marketing message of 'unlimited broadband'.
Sprint in in what they describe as the 2nd phase of Network Vision in which they consolidate their networks under updated 3G and new LTE networks. How this occurs is significantly gated by what networks the devices in users hands can operate - its one thing to talk about roll out of the various networks into spectrum, its another for subscribers to have devices that can work across them. In that one respect, FreedomPop, Earthlink are more fluid - they can roll out new devices targeted more at a specific network because of the expectations for use.. as modems/hotspots rather than 'fully mobile'.