Here's why:
* Evolution: Dragonite is the final evolution of Dratini, which evolves into Dragonair at level 30, and then into Dragonite at level 55.
* Dratini Location: Dratini is extremely rare in Pokemon Diamond. You can only find it in Lake Acuity, but the encounter rate is very low.
How to get a Dragonite:
1. Catch a Dratini: This is the most common method. Be patient and explore Lake Acuity frequently. Use a Pokemon with a high "Catch Rate" ability to make catching it easier.
2. Trading: You can trade with other players who may have already caught a Dratini or Dragonair.
3. Breeding: Once you have a Dratini, you can breed it with another Dragon-type Pokemon to get more Dratini eggs.
Good luck finding your Dragonite!