Now hold on, this has nothing to do with "dazzling everybody" or selfishly not supporting the Fighter. I, for one, would love to throw buff spells on my martials! However, often a Wizard player has to use their concentration on higher priority effects. It's one of my main gripes about concentration- the mechanic in it's current form was made to prevent people from layering spells, but often what it does is prevent me from using buffs on allies. I'd love to give my Fighter Enlarge, Haste, Fly, and Magic Weapon. But I can only do one. And by doing that, I can't hold enemies at bay with Hold Person, Hypnotic Pattern, Sleet Storm, Stinking Cloud, Wall of Fire, Evard's Black Tentacles, Banishment, and a host of other effects, which can potentially be far more effective in helping the group secure victory than letting the Fighter deal his full damage to a foe!
My current list of prepared spells is Mage Armor, Shield, Mirror Image, Misty Step, Web, Dispel Magic, Fireball, Sleet Storm, Slow, Protection from Energy, and Confusion. If I could put Magic Weapon on there (probably by removing Misty Step or Mirror Image), I'd be down to Dispel Magic, Fireball and cantrips for my contribution to battle, all to ensure one weapon used by my allies is magical (given that my party has a dual-wielding Ranger and a multiclassed Monk without Ki-Empowered Strikes, that wouldn't even ensure that all their attacks could deal full damage!).
There may be a circumstance where that's the best play, but so far, it really hasn't been for me. And this has nothing to do with selfishness or seeking glory- my party needs me to do certain things (like provide Protection from Energy while the Cleric is maintaining his Spirit Guardians), and I can only do so much at once.