theres one thing I can say about this:

Thunderstone


the fact of the matter is:

Pikachu is losing more battles against non-Team Rocket members

having him evolve and allowing Ash to put it in a pokeball will solve the problem of Pikachu being a dusty character plus it erases the idea of Ash carrying a Raichu on his shoulder^^

plus it lets other pokemon in his team get the spotlight

Bayleef was kicking butt instead of Pikachu in Gym Battles, but then he gave it to Oak.

The Pikachu thing is getting old anyways

All it does nowadays is shock Team Rocket

the big icon of pokemon must evolve to insure a different story

The stone evolvers aren't always made just for battling, there are also wild stone evolvers

or they could give Haruka a Pichu and she could train it and make it a Raichu to rival his Pikachu