But if the user prefers some other bootloader instead of Microsoft's or Apple's, then all bets are off. The idea of the "primary" OS being something other than Microsoft's or Apple's is not contemplated. For me, the non-GUI OS is the primary OS and the GUI OS is something kept around out of necessity, only used occasionally.
It is not as Apple, Atari or Commodore provided dual boot alternatives as well, and Boot Camp was more a result from survival than anything else.