The question isn't whether One Specific Mission might be replaceable. It's whether a war fought with the 1000 F-35's needed to do that mission can be successfully prosecuted against an enemy armed with A Million Drones (because yes, 1000x is just about the cost delta we're talking about).
Consider: Germany in 1940 had absolutely no answer for French heavy armor. There were weapon systems along the Maginot line which the wehrmacht couldn't counter, and everyone knew it. They didn't need to.
You're not even asking the right question. There's nothing magic about cheap drones. They can be effective supplements to crew-served weapons and light artillery for close combat. But they lack the range to be effective in the Indo-Pacific Theater, and when drones are designed with sufficient range they stop being cheap. Besides the range problem, cheap drones also can't perform the full spectrum of missions like deep strike, ASuW, interception, etc.
For all its faults, the F-35 at least has sufficient combat radius and survivability to be relevant in a major near-peer conflict (although it desperately needs a new and more expensive adaptive cycle engine). Until a better platform comes along the choices are essentially the F-35 or nothing.