Currently, Firebolt out does Magic Missile pretty easily in terms of what I would choose for a quick burst of firepower. Now, if I want to hit 3 enemies in one turn but sacrifice some damage to do it, I might choose magic missiles, but as it stands my wizard has been running around out of spell slots for 3 or 4 combat encounters now and I really don't feel any need to long rest to refresh them because him and my Eldritch Knight using firebolt on each of their turns is so absurdly OP that taking the long rest doesn't even seem worth it. I also just remember, in the middle of typing this, that my wizard has arcane recovery. Haven't used that once so far because cantrips are just so useful that his spell slots aren't really needed. The only time I've really gone out with spells so far is when the enemies end up getting to close to my wizard, which doesn't happen very often because of the nice little trails of fire and ice his cantrips leave all over the place to slow their progress.

But while we're comparing using cantrips to using say, 1st level spells, Firebolt out damages Magic Missiles. Max damage I can roll on Magic Missiles is 15 (1d4+1 per missile) while max damage I can stack up from a single firebolt is 18 (22 counting the burn at the start of the enemies second turn). That level of firepower already out performs several of the 1st level spells in terms of damage potential, and it also creates a fire surface that can burn other enemies that walk into it. Ray of Frost might not out damage 1st level spells, but considering how often it knocks enemies prone it doesn't really need to because it's basically a "skip an enemies turn for free" cantrip. And so far I haven't come across any spells as powerful as tossing down an Acid Splash to deal damage and reduce AC in an AoE, which just further increases my odds of hitting attacks afterwards.