A lot of people did/do watch TV linearly out of habit. Plop themselves down on the couch and watch.
Would they have started doing that if they had a lot of other options? Maybe in some cases. (Don't underestimate the desire of some people to have something on in the background.) But probably a lot fewer.
Something similar applies to a cable bundle. I lot of people have it. It's probably the easiest way to watch live sports. It may also be bundled in with other services they use. Etc. Canceling probably means changing some habits and losing access to at least some content. But they wouldn't necessarily have called up Comcast or DirecTV and initiated a subscription if they didn't already have one.