also, no modern game companies with any relevance use a FOSS license.
so the way i see it, gamers have two options:
stop playing videogames or
only play supertuxkart and dwarf fortress
neither of these would happen at a scale large enough to force game studios into making their games FOSS.
the only way i can see of making this happen is by either:
a series of very popular, targeted boycotts at studios, or
making governments regulate the industry.
and with the second option, history has shown that only small changes have a chance of passing. effectively abolishing copyright law for software is not something the EU will ever do, no matter how many signatures a petition gets.