Quoted By:
Humans in the Pokemon world have developed Matter-Energy Conversion, which has completely revolutionized things. Aside from storing Pokemon in Pokeballs, it also makes it trivial to transport material goods anywhere they're needed cheaply.
For this reason, 1) there's almost no existentially-devastating poverty in the Pokemon world, 2) wars fought over resources are non-existent, and 3) physical infrastructure between cities is relatively underdeveloped. Aside from farms and small towns, most rural areas remain untouched by development or are being quickly reclaimed by nature.