True but those are indies. An Activision, EA, or Ubisoft would have shoved that puppy right out into the cold as soon as they saw that the profits had peaked, cut off all but cursory support for the core product and then either moved on to attempt to reproduce the same success in exactly the same model with Minecraft 2 or peddled future updates and content as a series of overpriced DLC. Possibly both at the same time.
This new service is not exactly money for old rope. He is bringing in a new multilayer service, you're not being charged for Minecraft all over again but possibly being given the option to subscribe to a supplementary integrated service. Everything I have read says that you will be able to continue your current minecraft experience as it stands without this interfering.