More worrying is whether Costco and Walmart could be sued under this theory. Vizio sells very few TVs directly.
For the purposes of only this context, in which we are deliberating who is infringing on the GPL software blah blah, Vizio sells all of their televisions directly. The act happens when Vizio is paid for the product and never again. With very few exceptions, everyone with a stake in the software on that television loses their rights completely once the television is legally sold to a distributor. Nobody from then on is liable for the licensing structure of the software; in the eyes of the (American) law, the television is now a “thing” to dispose of as you wish and no more. That is impactful to both trademark and copyright law but doesn’t necessarily speak to, say, reverse engineering (i.e., DMCA).
The scenarios you’re describing aren’t hypothetical and routinely happen in commerce, and they are well-trodden ground legally. If they went the way you’re theorizing, too, you’d never be able to legally sell or loan a book to a friend. Your ability to do that is the exact subject you’re discussing.
When the second sale occurs, the seller must still obey the terms of the software license, which means the seller must give the end-user a full license which includes the ability to demand the source.
If it were otherwise, the GPL would be meaningless. Instead of the many BusyBox lawsuits, the companies could have "sold" their boxes, "bought" them back, then had no GPL obligations.
Lastly, without the GPL you have no software license and have no right to run the software.