Let's just look at the numbers quickly. Note, i'm not arguing with you, I am curious.Attack 8 times in a round for two rounds. By 20th level with damage extras, I don't think I wizard can match that kind of single target damage.
It's also white room replication. The wizards gets a limited number of spells for his book, and a limited number to memorize. The chances of memorizing everything a fighter can do AND also have utility AND social AND wizard combat is pretty much nil. So yes, a wizard can cast jump and go farther than a 20 strength champion, but is he really going to have that? No. Yes he can cast haste and get an extra attack, but in the scheme of things is that really the concentration spell he's going to be using on himself? Probably not.
The wizard CAN step on the fighter's toes a lot, but in practical game play this doesn't really happen.
Let's assume 1d10+1d6+8 for damage (magic versatile longsword with some sort of elemental damage) at 8 attacks is 136 points of damage. The chance to miss is present but negligible, so let's call it 90% of that for 122 points.
Meteor Swarm does 40d6 damage for 140 on average, but with a low chance of half damage. if there is a 20% chance of failing the save that puts us at the same 90% for 126. Comparable to single foe but of course meteor swarm can hit (optimally) 64 foes as well as hit flying enemies. I think the wizard does the fighters job here better.