One of the biggest problems in the Pokemon universe is that there is tall grass everywhere, and no one is mowing it. Maybe it wouldn't be such an issue if electric rats, fire dogs, and hypnotizing sloths weren't hiding out in it and attacking children at random; a pretty massive landscaping flaw. Of course, the process of actually mowing the grass would require a huge amount of effort at this point. Plus you would need lawnmowers capable of grinding through creatures made of pure rock and steel.
Sure, there are trade routes. And the tiny, isolated towns seem to be well-stocked in the essentials: It's not like anyone's dying of the measles or starving to death. But for some reason, the first town you come into contact with only has regular Pokeballs. No Superballs, or Ultraballs, or any of the better balls. They exist, and are being mass-produced. Why not ship a couple to the town surrounded by rattatas and pidgeys? You could probably make a fortune off of those small-town rubes. Instead, they're stuck with regular Pokeballs and regular potions. Now, if only they'd start mass producing Masterballs, maybe half my team wouldn't have to die to catch Mewtwo because I wasted the only one in existence on a Psyduck.