I think you are correct that 3D printers will not be in every home. I used to own a regular paper printer but I don't now. I'd rather go to the FedEx store and print stuff on the occasions I need to print documents. I wouldn't need to 3D print stuff all the time and couldn't afford to keep up with printer supplies and the latest printer tech. Id rather take my file to a 3D print shop (or send it online) and have the store maintain the printer.

Another example is that I have a photography hobby. I don't own a photo printer either. I do all my edits at home and then go online and select from a huge variety of physical mediums to print onto and have it delivered to my house in a couple of days.