What you fail to remember is the WiMax network WAS Sprint's to start off with. They unloaded the network and assets to Clear by trying to take the easy way out and become an MVNO on someone else's network. Sprint should have kept the network and built it out to start off with.
Clear could team up with the rural LECS- CentLink, Fairpoint, Frontier, etc and work on bringing them on as MVNOs and shareholders. Would give those companies new products and services to offer their customers.