Probably to add the overall flexibility of the Magic Your Way passes without hanging onto all of the different names.
You can get ALMOST the same impact by purchasing a Magic Your Way pass for the number of park days you want, and add the park hopping and Plus options. The only difference is that you'll have a fixed number of "Plus" visits rather than unlimited as was the case with the LOS. If you need those unlimited Plusses for a rather long trip, consider a Premium Annual Pass.