Don't worry about existing 2D printing giants
After all technology in 3D printing has progressed to some level of sophistication (I'm not sure what that level might be) I would expect HP and the other big guys to begin acquisitions of European 3D printer firms. The trick will be determining when to acquire; before it becomes too valuable, but after a great deal of the R & D has been completed. The products aren't valuable but obviously the technology is increasing in value.
This could certainly see some very lucrative transactions. Good way to make a fortune, even betting from the sidelines.