One place where I see a 3D printer being of use is when repairing things with hard-to-obtain parts. But of course you can't do this unless you have a database of parts you can print for the thing you are repairing. So like MP3 players (which did not explode until there was a database of downloadable songs that you could buy for 99 cents), we need a database of 3D printable parts for things like dishwashing machines and refrigerators and the like which can be downloaded for relatively cheap and printed on your printer which can be used to fix the broken component.
Of course not all parts can be replaced like this. But certainly there are plenty of components (such as the plastic drive gears in a garage door opener) which can be printed and replaced by consumers.
At the higher end I can see companies like auto repair shops using professional or pro-consumer level printers for printing harder, and more refined components for auto repairs, and even using 3D subtractive technologies (like CAD-driven lathes and CAD-driven milling machines) for making metal components which fail that do not require tight tolerances.
I think where things like the MakerBot gadget failed was that it seemed to be oriented around the idea that everyone could design their own components. But even in today's environment there are far fewer mechanical engineers and designers than folks like that give credit for.