I guess 3000 is the average, but it’s not a must have. Reviewers judge length by how many minutes it took them to finish reading an episode, not by how many lines it has (not that they know anyway).
A CC template takes up over 1500 lines, but it only takes up a few minutes of a story. An episode can have 5000 lines and still be 10-15 minutes long instead of over 20. My upcoming story is an example.