International flights go out with empty BF/GlobalFirst seats every day. Free/unsupported upgrades are not a published benefit for anyone, nor are they done unless there is an operational need. If this was a domestic flight where free upgrades *are* a published benefit then there'd be a valid issue here - but not for international.

If you want to sit up the front, either buy a ticket to sit there, upgrade with miles+cash, or buy the right ticket and use a GPU.