But you have to worry about this and weight cost and benefit, it's just not worth the hassle most of the time,

Perhaps you missed that I said, "And of course those are all real issues that can absolutely weigh against any benefits." The point still stands: "tl;dr: Potential benefits of IoT, while they certainly have to be weighed against the potential issues that currently exist, are still potential benefits."

I don't need to imagine, security, privacy, or out-of-date hardware and software is a huge problem there, too.

Sure, that certainly crossed my mind, but it's just not as bad at a technical level as IoT is right now, though as far as final impact that has to be weighted by market penetration.

I probably could have come up with a better example, but I was dead tired when I wrote that. :)