To get comparable quality as well as price, it's a decent number of years off, IMO.
Not to mention that GW and others will advance their own moulding techniques during that time. 3D Printing might reach a, "good enough," cheap and cheerful level, but I bet you even ten years from now you'd be able to tell a 3D Printed copy from the original.
I can't see them becoming the revolution people were saying they'll be for the last couple of years. Expense has to drop, they have to become point-and-click with extremely rare hiccups and no need for calibration. Even then, look at Printers. Woohoo, you can print out exactly what you want...and then a couple of years later WiFi hits, everyone's mobile and connected to Facebook to send and receive photos, and printers were relegated to the office and occasional CV printing spree.