If you have a business use for what they can print today, you already have one, and are likely contemplating buying a better one. If you have a personal use for the parts they can print, you probably already own one. And even if you don't have a real use for them, you may have one as a cool toy. But not everyone is going to buy the same toys as you.
Once they get a lot more capable (maybe not Star Trek replicator capable, but substantially better than they are now) then they'll become ubiquitous. Until then, not everyone needs one. I'm thanking you now for being an early adopter, but don't expect me to join you yet.