I mean, I literally just showed a build of Wizard that is at least as tanky as the tankiest "martial" in the game (Wild Heart Barbarian choosing Bear rage).
As part of that, I did not examine the DPR at all, just the defense spells. Using melee cantrips until 6, and then mixing regular attacks and cantrips for Big DPS, seems to be the thing to do, since that gives you cantrip-scaling damage plus a regular melee attack. Or if all you need to do is tank, one melee attack + Blade Ward for effectively +1d4 AC against all attacks (not just melee, nor weapon! "Whenever a creature makes an attack roll against you"), meaning if you go pure defensive, you at minimum match or exceed someone with full plate + shield (13 mage armor + 3 dex + 3 int + 1 minimum roll for Blade Ward = 20 AC).
There is an important distinction to make here.
I'm not saying a Wizard (or other caster) can't get benefit from doing this. They can.
I'm not saying a Wizard (or other caster) can't optimize for teamwork effect. They can.
What I'm saying is, it is more efficient to use the action economy to directly end things rather than to set things up to be ended. On average, your performance will be better if you are directly ending fights (or functionally doing so, "Save or Suck" kind of thing), rather than indirectly helping someone else do a little bit better at pushing things closer to the end.