jgsugden
Legend
Not more power. The same amount of power - but they have to spend those resources.Why? Why would a noble that is a spellcaster have any more problems keeping order than a noble that can't cast spells? Especially as the ability to cast spells sets him apart from other people and would be another argument as for why he should rule over others.
That noble may have power from charisma, money, connections, that wizards do not generally have. They have to use their arcane power to replace these resources.
Now, if you want to assume that all wizards are rich, charismatic and connected ... well, I'm not sure how they get that way when they spent so much time learning magic.