When 95% of the players aren't reaching those levels, why are they in a discussion about the class as a whole?
Person 1: "Wizards are broken and can do anything better than a specialist."
Person 2: "I've never seen that happen."
Person 1: "Well, it happens at level 15, so they're still broken and better at level 5!"
Person 2: "Um, it really doesn't work that way."
If you have an issue with super high levels, and as I said in other posts I haven't seen it at high levels, either, then there should be a discussion about level 7+ spells, not the class.