re: 3D printing
Truthfully, 3D printing could be the next REALLY big thing in computing ... but right now, people using it are just interested in being pioneers.
The reviews I've read so far of the most popular 3D printers (MakerBot's offerings, etc.) indicate they typically start having problems after the first 50 to 100 3D models are printed with them. After that, it's an exercise in frustration, parts replacement, and tinkering with tiny adjustments to figure out why things aren't coming out like they used to.
IMO, Apple is FAR from ready to release a 3D printer that "just works" the way people expect Apple products to work.
Honestly, what will really make this technology take off is a combination of a reliable, capable 3D printer that's relatively inexpensive to own and maintain PLUS really good, downloadable databases of printable objects.
Most people aren't that interested in the design work it takes to program up a 3-dimensional representation of an object to be printed. That takes a certain set of skills, as well as some level of enjoyment of doing it.
What the general public will want from a 3D printer is, for example, the ability to download and print replacement parts when they're needed for things like furniture. (Lost one of those pesky "L" brackets that you need to attach the corner piece to your computer desk? Just log in to the manufacturer's web site, specify the desk's part number, and find the part you need in a diagram online. Tell it to download the 3D print data, and make a new one.)
It'll be some years before we get there.
3D printer is overrated.
With that being said, I could still see every home having one within the next 30 years.