I bought it back during alpha for 10 bucks, and I've already more than gotten my moneys worth. If he decided to stop updating and call it finished than so be it. The mod community will take over.
I'm just glad this type of creative/survival whatever gameplay has gotten the attention. There are many 'clones' that are going to take this genre to the next level with or without Minecraft (as long as Notch doesn't pull a dick move and sue them all out of existence, if that's even possible).