I don't fully know how to explain malls declining. The obvious answer is Amazon.com and maybe that's pretty much the sum of it. But there's a social aspect to malls that you can't get from online shopping. And who likes socializing more than impressionable teens?
TV is a different story. Streaming is just a better way to watch. I keep an antenna around just for the shared-experience stuff like the news or special events. As with malls, I think the diminished offerings on TV are determined by their remaining viewers, not the other way around.
Now if you want a case where I feel the product itself whittled the audience down to a premium niche, take arcades. For a long time arcades thrived on single-coin currency. In the 80s one play was one quarter. Then their crowds were thinned by home video game systems. So what did they do? Doubled the price, and doubled the coins needed to play. This is the exact opposite of the proper reaction. When there's downward pressure on prices due to competition, the correct response is to decrease your prices, not increase them. And don't give me any stories about recouping costs, because there's no fixed cost for a gaming session. They needed more people in the door, not more money per play. I'm sure the manufacturers drove this, but I don't know the whole story. All I know is, no one seemed to have the willingness to go against the trend. But among the few arcades that still exist in my area, guess what they typically are? Nickel arcades or straight-up free play with a cover charge. Pretty much what they needed all along.