Commercial displays are not tvs. Quite often the refresh rate is terrible and you cannot watch action movies on it, because it was designed to show static billboard ads.
Not to mention if you want an OLED display, any sort of commercial variant of that will be $10000+ and marketed to Hollywood producers and other creative industries that care about color accuracy.
If it doesn't have the passphrase for wifi, how is it going to connect? I rarely see unsecured wifis around neighborhoods anymore. For copper/fiber, you're not going to hook it up to keep it disocnnected.
Guest wifi does not mean it is unsecure, it is simply just another logical network. Sure amazon could equip their trucks with wifi I suppose and maybe some TVs would have good connection to update fast enough while a truck is there without a lot of tcp retransmits due to lack of efficient lack of penetration but that's not going effect all brands and surely it isn't something that is currently happening in a large effect.
You could talk about hypotheticals in the future sure but they aren't going to scan for these magical "network ports" that are just hanging around the ether. It needs to have a connection and one that is reasonable in quality and time.
Open networks have no passphrase. Otherwise they wouldn't be open. And yes they're less common but it doesn't mean you're neighbor can't set one up at any given time.