The wizard is strong until an anti-magic field comes up. Then the reality bending magic users think the game is unfair that the hit stuff until dead characters deal too much damage. Eventually the player will realize, "Wow there are a lot of beholders in this campaign."
It always seemed strange there wouldn't be a beholder in every massive city. I mean, the ability to basically stop any magic user in their tracks seems kind of... useful in a world fill with magic? 4 beholders in one room may seem like overkill, but if an area needed protection, why wouldn't- oh wait all Beholders are borderline insane/or completely insane and refuse to work together. DM forbid that tiny, little, miniscule detail about one creature gets changed.