>>49487585They were always based on the Nintendo handheld of the day, likely the device you were playing the game on if you played during its original release.
They were never going to make a Switch Pokedex. It's simply a reflection of the times. People don't carry around a dedicated device for each function anymore. It's all an app now.
I remember the old designs fondly. There was a lot of creativity in them. But hey, at least it's not another Rotom phone.