Earlier quoted context omitted.
I have a hard time believing that that was the average monthly cost of a cable subscription. Mine was never more than $30-40 when I needed cable for the internet.
When I had cable the $30 plan was the "just the stuff you can get OTA plus some shopping channels" plan. If you wanted actual cable channels you had the choice of: 1. "Basic" bundle, $60 + $20 in fees + $8-15 per set to rent the box. Got you ESPN, Food Network, SciFi, Cartoon Network, USA 2. "Complete" bundle, $100 + $20 in fees + $8-15 per set to rent the box. Got you BBC, a bunch of foreign language channels, Starz…
Yet. IIRC, when cable started, it didn't have ads either. It was its selling point.
Advertising is a cancer on society that infects and poisons every communication medium available. It has already metastasized to streaming platforms, though it's not conspicuous yet. You don't have to watch interstitial ads between episodes of your favorite show on Netflix, but if that show is a modern production, it's likely overflowing with product placement ads. When that and other means of making easy money get used up, you can be sure that overt ads will follow.
"All this has happened before, and all this will happen again." And that's a salient argument in favor of torching the whole advertising industry to the ground.