Your argument is ignoring a few relevant points.
9d6 Mind Control is 45 points. The game mechanics may be simple, but it is a very powerful spell, butting up against (or exceeding) heroic campaign limits.
Fighters may have access to constructs the mage does not (pushing, haymaker, martial arts, etc).
Depending on how the magic system is designed, the mage may not have access to all of their spells simultaneously. My Vancian system, while it uses a Multipower, still requires wizards to memorize their spells in advance and restricts how many spells can be memorized at once. Charm Person (the above-described Mind Control) would take an hour to memorize and take up a substantial portion of most caster's spell pool.