The trouble is, games age quickly

If some company develops a graphics application or a web browser or a new compiler then there
is a good chance people will still be using the code or code descended from it in ten years'
time.  Paying a ransom may be good value for money if you take a long-term view.

But a video game is played for a year or two and then looks dated and boring.  Graphics and
levels written for one game can't be reused for another, and even the game engine will tend to
go out of date quickly as hardware capabilities improve.

So I'm not sure that ransoming software to release a GPLd version is an appropriate business
model for games.