Discussion on answer by PixelMaster: Can the Wish spell be used to allow someone to be able to cast all of their spells at will?

Imported from a comment discussion on https://rpg.stackexchange.com/questions/158502/can-the-wish-spell-be-used-to-allow-someone-to-be-able-to-cast-all-of-their-spel/158504#158504