It's what started their cope about the graphics looking bad. Gen I was rough but they were newbies and Gen II they came into their own peaking in art style with Crystal. Then they get a much more powerful system to work on and they couldn't adapt and had to make the most basic looking game possible. They got some cool things going on like water reflections, but losing out on the day/night system proved to be a MONUMENTAL downgrade to most people. They clearly struggled to do the new Pokemon sprites too. It wouldn't really be until Platinum where we started getting pretty consistent sprite quality
Even Sugimori's art took a massive shit in this era, outside of the protags EVERYONE looks so much worse than the character designs of Gen I+II, literally every character has been hard-carried by their ORAS redesigns. Without them I don't think they would ever be thought about anymore
