We're talking about bunker-busters - the MOAB is not a bunker buster. It's an airburst weapon designed to clear out large open spaces, and isn't effective against hardened bunkers.

No reasonable amount of quadcopters could match a bunker-buster. Surface explosions are not very effective against buried targets.

The weight and density of the bunker-buster is extremely important to its operation. When dropped from a high altitude, it breaks into the bunker with sheer kinetic force, and then explodes once inside.

>How many $200 quadcopters delivering blow after blow to reach the equivalent damage to a single <orders of magnitude larger purpose designed munition>?

How long do I have to piss on a steel plate to get the same effect as a waterjet cutter?

About the same answer.

Those are entirely different missions. A GBU-43 MOAB is used against soft targets on the ground. A GBU-28 is used against hardened buried targets. It's simply physically impossible to dig a big enough hole with a bunch of small drones or bombs: the only way to penetrate deeply enough is with a hard object moving really fast.

A MOAB apparently has the equivalent of 11tons of TNT. A drone carrying a grenade has up to 180 grams. So you need about 61 111 drones to deliver the equivalent explosive. At that point it might be cheaper to just bring the MOAB.