I think its a reasonable statement to make that there are far far more enemies that deal damage than deliver int or wisdom saving throws.Yes. Frequent. If you are being hit. Wisdom saves can easily instantly snap out your concentration in fights that matter. Actually, one should really look at fights that matter. Enemy spellcasters are usually in those fights. Illithids are in those fights.
And while you could absolutely run a game just chock full of Illithid...I hope we can agree that is not the typical dnd game.
Now I am in the camp that says the wizard is just fine, but I do think when it comes to saving throws the con bonus for the sorc is a bonus on top of what the wizard gets.