Most of these devices are running Linux, so I would say the fact manufacturers are not shipping "the scripts used to control compilation and installation of the

Most of these devices are running Linux, so I would say the fact manufacturers are not shipping "the scripts used to control compilation and installation of the executable" at time of sale or promptly upon request, is illegal already. The GPL2 actually foresaw developers failing to ship critical bits that are required to run the software. There's just little will to enforce it.