If a free software program decided to stop supporting X and Wayland, it would be because no one cared enough to contribute the code for continued support, which

If a free software program decided to stop supporting X and Wayland, it would be because no one cared enough to contribute the code for continued support, which would imply that very few people were still choosing to use X or Wayland over Mir. If Mir really ends up being that wonderful, why shouldn't it win? How does one free software program replacing another constitute the death of free software?