You can cast all the spells you want, it's great knowing spells.. but they're ultimately only as valuable as the problems they solve. Any old wizard can cast spells..

But knowing what to cast the spells at.. finding the thing that NOBODY ELSE IN THE WORLD thought as a target for spellcasting, that's where the money's at, that person can then get "fu" rich by casting spells OR by just paying some run of the mill wizard to cast spells. The ideaman gets the money. Sure, you can be both a wizard and ideaman, and that increases your changes, I'm just saying the idea part is the tough part, not the spellcasting.