Why does Pokemon need a post game?
Gen1 barely had post game
Gen2 had barely any post game (counting Kanto as post game when a it continues the story)
Gen3 didnt have a post game till Emerald
Gen4 was the first one to jave pist game and its shit.
Gen5 IS shit
Gen6 goes back to status quo of minimizing post game.
Gen7 actually uses the lore to build its post game around, better utilized in Ultra versions