What I ment was; A company like GE is capable to produce the printers under license of Arcam. In case of a large demand in numbers (500 printers within two years?), or a demand in specialised printers for a specific job. Don't you think licensed production is a possibility? https://en.wikipedia.org/wiki/Licensed_production
Nobahamas may have been asking "What's to stop GE / Siemens / DMG Mori Seiki etc. (or Arcam) from making their own LASER machines?" If not, I see that as a good question. I've heard that the laser technology is more open (available) but don't know what, if any, limitations there are.
I don't have any real understanding on how patents legally (i.e. exact protection terms) protect inventors and manufacturers.