I've likely missed it, but while we've talked about the weakness of high-level fighters to high-level wizards, what about the reverse? Because if high-level wizards are weak to high-level fighters, then there's a balance there.
Take a fighter with the duellist or GWF styles: at 20th level, he can attack 5 times (assuming d8+2+5 or d10+5) if he uses Action Surge. That's about 60 HP damage assuming all attacks hit. A 20th level wizard has an average of 74 HP without Con bonus. That's a credible threat. Even with a +2 Con bonus, the wizard is still going down on the second round.
It's not quite save or suck, but very near.
[MENTION=5889]Stalker0[/MENTION] did an analysis here.
Also, I'd like to point out this isn't Wizards vs. Fighters: all PCs have this deficiency against magic. I suspect Wizards will actually have the worst saves in a group. Their primary stat isn't a saving stat like Clerics and Rogues, they get the fewest stat bumps, and their primary save stat offers very little other than the save improvement to the character unlike the Fighter.