Why the obsession with forcing Stormwind/Orgrimmar as the ONLY hubs that matter?

This started back in Cata when the Cata Portals were only in Orgrimmar and Stormwind. Then later in Cata, where the Transmogrifier was only in the newest City and Stormwind/Orgrimmar. Now, with 8.1, they removed the portals from Pandaria, because they're making a Portal Room in Stormwind. I don't understand why we can't have these portals and features in other capital cities. The only time I see people in Ironforge is Winter Veil, I rarely see anyone in Exodar, Silvermoon at least has the RP Community, Darnassus straight up no longer exists as a capital city thanks to Slyvanas...I just don't understand why Blizzard focuses on making Stormwind/Org the only capital cities that matter. Is it just to show the illusion of their being a lot of players playing the game?