I am not suggesting that you build unmanned F-15s for the $4mm each that you can build a Predator for. That's patently ludicrous I agree with you! So no fancy engines, nor fancy avionics. Also don't bother with swarm AI, have people on the ground handling targeting. Don't develop a billion dollar solution when $50k/year (roughly) works just fine.
What I was suggesting is that you build a bunch of aerial SAM launchers. Take a Predator, put something that can receive targeting info on it, arm it with air to air missiles. Deploy many of these in the sky. Then for every 10 missile mules, you put up a single command and control Predator. It has the fancy equipment to ensure that you can actually do targeting. Then put a transmitter on all Predators which can be turned on such that you can't detect which Predator is the command and control one.
Let's suppose that you could create this fleet of 11 for $4mm * 11 + $2mm * 10 + $20mm * 1 = $84mm This is very conservative in my mind because at this point we're basically paying US prices for the gear.
Again, we're not going for the fanciest, best, most high performance stuff ever built. Use old designs, don't worry about the best survivability, don't make them too rugged and thus don't drive up the cost. We're going for The Innovator's Dilemma style worse-is-better so long as it's functional enough to mule up the ordinance.
You can now afford at least 2x of these 11 unit Predator swarms for every 1x F-35 that can be deployed. An F-35 only carries 10 air to air weapons and that's when loaded with nothing but. The odds they get both command and control Predators on every engagement is statistically slim provided you're talking about at least a few dozen engagements.
That means that just playing a numbers game you're going to shoot down the F-35s and because you've got so many damn drones in the air enjoy quite a bit of air superiority. It's not exceedingly difficult to imagine that if the sky was thick with these things that the F-35s might not get all their ordinance away before being shot at making the grinding more painful.
Could the US manage such a feat of engineering discipline and fast-track development? NOT A CHANCE!! If you're thinking that this is unrealistic based on how things work in the US you're 100% correct. But to suppose that no other industrialized country in the world could embark on such a venture and succeed? If you believe that please stop reading HN because startups could never work/win against the entrenched giants who have all the advantages.