>>35871505People really need to get over looking for some line to draw to say when things go wrong.
It's almost always a steady decline, not something you can point out directly.
Pokémon has been going up and down with a distinct downward trend (in particular after Gen 4). There's no specific point you can say was the one thing that made it what it is today. It was a series of shit choices on the part of the devs over years, not just one unmagic moment.