A few fairly straightforward reasons why:
- Their character arcs are both complete, removing their relevance from ongoing/new adventures, which need feature only Captain Jack Sparrow.
- They were never the box office draw of the earlier films, and replacing them with new allies and frenemies (like Penélope Cruz) helps keep things “fresh”, and helps less creative movie execs figure out what additions/subtractions can help bring home more bacon.
- Neither is a compelling enough actor/character in their own right to warrant continued exposure within the franchise – it just takes time away from the much more bankable “Johnny Depp Vs. X” storylines we are bound to see in future films.
Why aren’t Orlando Bloom and Keira Knightley in the next Pirates of the Caribbean film?