How do Professor Oak's grandson Gary Oak doesn't go to the Unova Region when the Pokémon: Best Wishes started?

Just like it's said, Gary Oak decided to help his grandfather so it doesn't seem likely that he'll be going around the regions as fast as Ash since he'll be researching.

Also, just in case you haven't noticed, there are barely any of the old characters from the previous seasons in the Pokemon: BW season. So, for example, if the main characters Brock or Misty or the guys from Hoenn and Sinnoh haven't appeared, I doubt Gary Oak would appear ever since he became a less seen role.

Are you trying to say- Why doesn't Gary Oak go to the Unova Region?? Gary Oak decided to be like his Grandfather- study pokemon. I hope to see him in the Unova Region but most likely not. This season focuses on Ash and his adventure in Unova with Iris and Cilan