>>19291875They started marketing it suddenly. i.e. it appeared in the anime and everyone thought Ash was going to catch it. Additionally it was featured in the new mystery dungeon game and it was one of the few pokemon who got shown off in amie before the game came out. Because of this people thought it was going to get an evolution, just like when they started featuring eevee all of a sudden in the anime and Sylveon got announced.
