Also worth noting that with a lot of TVs, you can download firmware updates to a USB stick, then install them directly to the TV.

Occasionally the out-of-the-box firmware on TVs can perform poorly on certain input modes, so it's nice to have an option to get the latest patches without opening yourself up to tracking and ads.

That said, the idea of a TV needing patches is thoroughly unappealing.

I have heard reports that some smart TV's (and other "smart" devices?) will sometimes connect to any open wifi within range without user consent or knowledge.

Not if you use a box like Roku, etc.

Won’t the roku only needs to be connected to internet and not tv itself? Right ?

HDMI optionally does support that, but almost no devices actually do.

In the future, won't it become increasingly difficult to keep your TV disconnected? Anything you connect to it will provide it with an internet connection.

Don't see any evidence of that actually happening as of yet. Would more expect that they'll just make them stop working entirely without a connection, instead of adding fancier ways of connecting them.

Maybe we'll have "HDMI condoms" that connect two cables and drop all packets relating to internet sharing.

They could create an HDMI condom so you can't have network connectivity over HDMI. Similar to USB condoms.

Also... what if they put a 5G SIM card inside the telly? Now that would suck.

That does seem inevitable. Time to build a faraday cage for our TV's.