A major difference things like this don’t take into account is animation.
When the original pokemon were designed, they were just static six-bit colorless sprites. They had no clue what was to come in the next 20 years.
Over the next twenty years, pokemon has become insanely popular. Disney level popular. Each game has increased the animation until each one now has a fully animated CG model, rendered in far more detail than the first gen Gameboy sprites could ever dream of. It’s had thousands of cartoon episodes and around two dozen movies.
The newer designs are-
- Much easier to animate, and more importantly,
- Significantly easier for children to draw.
And that’s ultimately what this franchise boils down to: it has to be accessible to children.