Eventual unlimited for all?

Now that all carriers have the option for unlimited, does anything think it possible for TMobile (or any other carrier for that matter) to actually ditch all data plans completely? Not just for new plans but simply ditch all packages for the past and make each line unlimited and maybe pay extra for tethering or something? I just feel like with TMobile wanting to make things simpler this might be the route to go. Packages would be unlimited for all, but then the options would be for maybe no tethering, 1 GB, 5 GB, 20 GB and 100 or something? Just been thinking about it all day and wasn't sure the possibility behind it and wanted to get other thoughts.