It would highly depend on the contract between Vizio and their suppliers no? In particular if the lawsuit finds that anything from the supplier (like e.g. the display driver) is part of the GPL violation the contract likely contain clauses that would force the supplier to provide source code. Otherwise Vizio has grounds to sue their supplier.
That's the beauty about going after the big customer facing companies, it offers the strongest leverage.
Suing a rebranding company is actually the dumbest move. If I buy Ford trucks wholesale and put my own logo on the grill and my own software on the entertainment system that uses GPL code in violation of the license, you can sue me until the cows come home but you are never going to get all the other software Ford has on that car.
The idea that a court could compel Vizio to provide enough source code that you could run your own OS on the TV is pure fantasy. You would need to obtain binary blobs for firmware and drivers from an original TV, and distributing them would in turn be software piracy.
It happened with routers, the OpenWRT project is a result of GPL enforcement against Linksys. There is no reason the same can't happen with TVs and other devices. If the company can't comply with the GPL, then at minimum the lawsuit could be transferred to the suppliers, or at worst the company can stop using Linux and other software they violate the licenses of. There are plenty of non-copyleft or proprietary projects they can use too. Whatever software Vizio use that isn't subject to GPL requirements can be rewritten or replaced with other components. The main thing is that the GPL code get released.
It would highly depend on the contract between Vizio and their suppliers no? In particular if the lawsuit finds that anything from the supplier (like e.g. the display driver) is part of the GPL violation the contract likely contain clauses that would force the supplier to provide source code. Otherwise Vizio has grounds to sue their supplier.
That's the beauty about going after the big customer facing companies, it offers the strongest leverage.