A Wizard does not need to have the ability to eclipse a melee specialist in their specialty in order to provide as much of a contribution to the party. They just need the ability to do different valuable things.
Magic Weapon will improve most melee character's damage by around 10% and then add another d12 to every hit on top of it. Over the course of a fight if a barbarian hits 5 times that is 5d12. That is extremely powerful.
Against a higher level monster Ray of Enfeeblement will reduce the outgoing damage of the monster by 25% on a failed save. That's immensely powerful.
Against a high level monster Fear will reduce incoming damage by 25% and outgoing damage by at least 10% for one round for every other character in the party for one round. The next round you will get about half that effect. This gets better if you stack it with other conditions like Sickened from Goblin Pox.
Grease can knock several creatures prone and help melee bush whack them much more effectively.
When monsters are spread out electric arc allows a wizard to attack two monsters within 30 feet of him. On a failed save he only needs to roll a 2 to kill a goblin warrior or a 3 to kill a kobold warrior.
Against monsters with resistances against physical damage like a Spider Swarm (Creature 0) the single target damage of Shocking Grasp is pretty strong. A wizard's range of damage types also allows them to more effectively capitalize on weaknesses than martial characters can. If a wizard catches two Spider Swarms in a Burning Hands spell they will do 2d6+5 to each thanks to its weakness to area damage while a ranger with two short swords will be dealing 1d6-1 on each hit.
Many of an Arcane Caster's damage spells also have secondary effects. Hydraulic Push moves the target on a successful attack and does 3d6 damage. This can be used to allow melee to do their jobs better.
I will admit area spells are fairly lacking at lower levels. Grim Tendrils is much better than Burning Hands, but potent area effects do not come online until 3rd level spells really.
Spellcasters have plenty of ways they can be excellent and impacting members of the team. They do not need to eclipse specialists to have value. They bring unique abilities and talents that can make hard encounters much easier, can easily get around resistances and are adept at exploiting monster weaknesses.
This reads as not a little defensive, as if we needed a reason to play a Wizard.
When we're trying to agree something has happened with the potential of the Wizard spells that directly defeat monsters.
Why not be confident the Wizard has other things to offer and simply acknowledge these spells are gone down the drain?