I challenge the premise. At least in the United States, the number of subscribers to commercial-free cable channels has decreased significantly in the last 10 years, during which time the number of subscribers to streaming services which show fewer or no ads has increased significantly.

I think it was more of example as using term ”popular” in different context, regardless of it is true or not. Arguing if it is not true, does not take this example away.

Of course it does, because “popular” in the original example was referring to their ubiquity and lack of over viable alternatives. An example of a once-dominant product that appears to be losing in the market to a fast-rising new alternative is not analogous.

Argument goes then more for “is this scenario possible at all for term ‘popular’?”, when it certainly is. Example was just weak.

Another example could be, why driving a car is “too popular” on country side to move between places. It might be popular, because there is no public transportation. Is the situation same with public transportation? Can we call it popular, because it is forced?

The whole point is that there's a difference between saying that the popularity of a product can be caused by the lack of what would be a viable alternative (like your example of public transportation versus cars), and saying that the popularity of one feature of a product is caused by the lack of alternatives that do not have that feature. The latter is more like saying "the popularity of 4-wheeled personal automobiles is caused by the lack of 3-wheeled personal automobiles on the market" or "the popularity of touchscreen smart phones is caused by the lack of smartphones with physical keyboards on the market."