If it’s bad, it will never be forgotten. Let’s take the Star Wars Holiday Special, for example, which, as of writing, is still not on Disney+. Other de-canonized shows and movies are on there, so why not that one? Well, we don’t know that answer for sure, but I can speculate that given the special was critically panned at the time and widely recognized as a colossal misstep by Star Wars, it’s not something Disney would like to openly promote viewing. And yet, it was so bad that people haven’t forgotten, and copies of the special are still widely available on the internet.
Source: Cinema Blend