I know RedHat used to to this before they found a loophole in the GPL, but I never heard of anyone doing it with games (games with proprietary assets don't count). Another idea is to sell physical copies for collectors because collectors will naturally go for official copies.
They didn't find a loophole, as if any of their customers ask for the source, they have no choice give it to them.
To spite the exercising of freedoms, redhat cancels support contracts, but really the proper solution for that is for every single customer to demand source code, always, or at least a substantial amount, as it's not like redhat is going to fire every single customer.