My main concerns are these: Just like a patent troll can hold a company hostage with a patent, can a "copyleft" troll / lawyers hold a company and users host

My main concerns are these: Just like a patent troll can hold a company hostage with a patent, can a "copyleft" troll / lawyers hold a company and users hostage with copyleft lawsuit? If the zfs + linux kernel NAS products become wildly popular, can a lawyer + a kernel src copyright holder sent letter to NAS company + its customers and demand $500K or $1-10K per users to ask them to pay up?