[adrianmonk]

The important implication of broadcast TV being "free" isn't that there's zero cost. It's that there's no subscription.

Subscriptions mean you have to pay a certain minimum amount, even if you want to watch just one episode of something. That's a much bigger burden than changing the channel.

Yes, in theory you can carefully manage things and cancel as soon as you've watched what you wanted, but in practice that effort is a cost too (like watching a commercial is a cost).